Formal Logic and Self Expression

F. Kenton Musgrave

Pandromeda, Inc.
15724 Trapshire Court
Waterford, VA 20197-1002


Abstract

The digital computer can be used to synthesize images of Nature from first principles of mathematics and the natural sciences; these images can in turn serve as vehicles of self-expression for the artist directing the synthesis. This peculiar artistic process juxtaposes the deterministic formalisms of the scientific method with the subjective aspects of visual aesthetics and with the pursuit of artistic self-expression, which may best be characterized as a spiritual undertaking. We claim that this novel creative process is unprecedented in the visual arts--not only because it can be practiced only with the aid of powerful computers, devices that are a recent phenomenon, but for deeper reasons as well. Furthermore, we claim that this new process has exceptionally deep conceptual underpinnings entrained from the mature formal disciplines from which it derives. Generally, practitioners of these formal fields--scientists and mathematicians--are not fully cognizant of the disciplines of visual aesthetics, just as practitioners of the fine arts are (though with arguably greater awareness) generally ignorant of the finer points of science and mathematics. This division of expertise has lead to the false contemporary cultural notion that the two methodologies are somehow inherently separate and irreconcilable. Not so, we will argue. Yet mutual appreciation will require mutual understanding of the richness of the underlying disciplines; the purpose of this essay is therefore to illustrate that art and science can be brought together in a single creative process, and to convey some appreciation for the depth of the resulting fusion. This essay is addressed to the intelligent layperson: We proceed by elucidating certain formal methods and how they relate to the computational process of image synthesis, then by pointing out some of the implications to the visual arts of working in this new process, and finally by illuminating the philosophical dilemma posed by the pure use of formal methods as the means to achieving qualitative, even spiritual, humanistic goals.


 
1. Introduction: The Birth of a New Art Form
 
The advent of the digital computer represents a rare event in the fine arts: the birth of an entirely new creative process. This process is distinguished by its deep conceptual roots in areas normally held as alien to the arts and by its peculiar deterministic mechanism of expression, which is wholly novel to the practice of artistic creation. In this process the computer acts as a potent engine of interpretation, reifying in images the dry but austerely beautiful abstractions of formal scientific models of the universe we inhabit. The images so created may in turn become artworks, spun from a process based upon philosophy, mathematics and the physical sciences, and entraining the rigor, beauty, and intellectual depth of those fields. Art and science, so often viewed as mutually inimical and irreconcilable, come together in pursuit of the common goal of visual aesthetics.
 
In the seventeenth century Rene Descartes and Isaac Newton, as natural philosophers, fleshed out a world view so compelling that, if the average educated person in our society today stops and thinks about it, it seems to be "the obvious way that things are": In the Cartesian universe with Newtonian dynamics, if we knew A) the position and velocity of every particle in a closed system and B) the rules for their interactions, and we had sufficient power to compute all those interactions, we would have the power to predict the future, forever, for that system. If the closed system in question were the entire universe, this would have profound philosophical implications: There could be no free will; it would imply that we are all witless automatons, mere puppets in some sort of deterministic, already-written cosmic script. It would affirm the nihilistic philosophy of fatalism, and undermine the basis of human morality: that we have a choice in matters, and that what we choose to do--and not to do--makes some kind of a difference.
 
In a broad view, the new artistic process we describe here juxtaposes formal logic with human self-expression. The former is founded upon determinism; a philosophical assumption that denies the possibility of free will. Self expression, on the other hand, is an ultimate manifestation of free will. I emphasize these two extremes, to highlight what is interesting in this new process. One may substitute "aesthetic judgment" for "self expression" throughout the text, but I will maintain the latter usage, in the interest of contrast.
 
As a practitioner of the new process, I will attempt to illuminate both its specific concerns and the significance of its links to the fields of formal logic, the natural sciences, and computer science. While the arguments presented are necessarily technical at turns, I will make every attempt to keep them comprehensible to the intelligent layperson. As well, I will attempt along the way to point out some of the implications of the advent of this new way of working, and how they relate to current trends in the visual arts.

1. 1.  The Thesis
 

The thesis I propose is this: Self-expression in representational imagery may be obtained strictly through formal logic; and the practice of doing so marks a discontinuity of significant import in the history of the creative process. In addition, I claim that the resulting artworks are conceptually enriched by the intellectual underpinnings of this approach: When an artwork represents the unaltered result of a deterministic logical derivation, it entrains a conceptual depth and richness not commonly achieved in the realm of visual arts.
 
Only time and our culture can determine the validity of the first two claims I make. The last I can illuminate; that is what this essay attempts to do.

1. 2.  Foundations

Science is the discipline of observing Nature and deriving potent and internally consistent descriptions (models) of systems observed therein. Mathematics is the language of science; it provides both a terse notation and a logically consistent framework in which to couch such descriptions. Computer science is the study of the complex logical system that is the computer; it is largely based on the discipline of mathematical logic: The operation of the modern digital computer is described completely by, and at the lowest level is literally implemented in terms of, the predicate calculus of formal logic.
 
It is worth pointing out that it is a specific sub-branch of computer science, numerical analysis, which concerns itself with the problems of performing mathematical computations with a digital "computer. "Note the sudden appearance of quotes around the word computer--it turns out that this appellation is a misnomer: a (digital) computer is more rightly viewed as a symbol manipulator, a string re-arranger,[1] than as a mathematical calculating device. I point this out because this "string re-arranger" model of the computer will be essential to my treatment of the computer as an artistic tool and process.

1. 2. 1 Formal Logic and Formal Systems

Our arguments are based on the discipline of formal logic, the study of logic in its pure form. Interestingly, a first college course in logic will typically be taught in the philosophy department--logic being, of course, the foundation of reasoning and reasoning being the foundation of most precisely communicable human understanding. A first course in formal logic may also be taught in the philosophy department. Formal logic is codified in the predicate calculus, which explicitly lays out the valid and invalid forms of logical inference as well as the minimal set of rules required for full logical reasoning. More advanced courses in formal logic are likely to be taught in the mathematics department, under the moniker mathematical logic. Mathematicians are intimately involved with formal logic, as all of their work is in the domain of the logical framework provided by formal systems, the reasoning systems of formal logic. Finally, formal logic is also taught in computer science departments, as computers are implemented in terms of logical operations; thus all theoretical models of computation reduce to the study of formal logic and formal systems. We see then that formal logic is already a highly interdisciplinary field; in this essay we will extend its scope by establishing a direct linkage to the visual arts.
 
A formal system is a sort of game; it is a fundamental concept of mathematical, or formal logic. [2] For our purposes we may think of a formal system as a set of given input strings, called axioms, along with a set of rules for performing transformations on, or changes to, those strings. The latter are called rules of production or rules of inference. Consecutive application of the rules of production to the axioms constitutes the derivation of a theorem in the system. The specific sequence of application of rules of production in the derivation constitutes a formal proof of the theorem.
 
A simple, illustrative example of a formal system is Hofstadter's MIU system. [4] In this system, the only recognized symbols from which to compose strings are the characters M, I, and U. The only axiom, or starting (i. e. , input) string is MI. There are four rules of production that may be applied to the axiom and its successors:
Rule I: If a string ends in I, you may add a U to the end.
Rule II: If you have Mx, where x is an MIU string, you may add Mxx to your collection.
Rule III: If III occurs in a string, it may be replaced with U.
Rule IV: If UU occurs inside a string, you may drop it.
Every string derived from the axiom by these rules of production may be added to your collection of valid strings. Hofstadter challenges the reader to derive the string MU from the given axiom MI, using the rules of production given for the formal system. Note that there is no ambiguity in these rules, no "maybes" or "kind-of-likes. "The results of an application of a rule are deterministic; but there is free choice in the order of application of the rules.

This is a very simple formal system, but it reflects exactly the behavior to which a computer is constrained: modifying strings by the application of well defined deterministic rules of production.

Why do we bring up this rigmarole? Because this is exactly how a computer operates. We can describe the functioning of a computer completely through this kind of formal treatment; all other "higher level" functions of a computer are built on top of, and implement different instances of, such formal systems. Formal systems have, in turn, been studied intensively. Early in this century, Bertrand Russell and Alfred North Whitehead [13] set out to map all of mathematics into a single, unifying formal system; their difficulties were shown to be theoretically insurmountable by Kurt Godel in his famous Incompleteness Theorem. (This theorem demonstrates that, for any 'sufficiently powerful' formal system, there exist statements that are neither inconsistent with the system nor provable or disprovable within the system; in short, the system has nothing to say about them. MU is such a statement in the MIU system. ) In short, great minds of our century and before have worked on the ramifications of the machinations of formal systems; in fact, many smart mathematicians and logicians continue to do so today.

The consequence to us, of all the above, is that when we are using formal logic (i. e. , formal systems) we are "standing on the shoulders of giants," intellectually. There is a rich, preexisting mathematical and philosophical body of knowledge in this area, which we are implicitly drawing upon when we use the computer.

1. 2. 2 Artwork as Theorem

How does this concern us, artistically? As it turns out, all computer programs can be mapped into formal systems. Thus, when we use a computer, we are using a formal system; we are utilizing formal logic. Every time we execute a computer program, we are causing the derivation of a theorem in a formal system. "So what?" you might ask. This observation might seem to trivialize, to render vacuous, any claim that the derivation of a theorem in a formal system is in any way something special or intellectually weighty--after all, computers do it all the time, day in and day out, all around us.
 
But how often do we call the result art? ("Too often," indeed. ) How often is the artist cognizant of these arcane machinations? How often can the artist claim to have consciously engineered the entire procedure? When the formal system involved is a computer program written specifically by the artist for the purpose of producing the artwork, when the program itself embodies much or even most of the power to create the work, when the artwork represents something that could not have come into being in any other way, then these observations vis a vis formal logic become interesting. Indeed, they gain great import.

1. 2. 3 Theorem as Self Expression

It is one thing to label a theorem derived in a formal system a work of art; it is another to claim that work of art represents self-expression on the part of the artist. Scientifically, such a claim is weak, as it can be verified only by the artist; no independent formal verification is possible.   I maintain that the claim can nevertheless be valid, and is even readily verifiable in many cases, if only qualitatively (as opposed to quantitatively). There exist examples of such artworks--the pure output of a computer program--wherein it is readily evident that something of the artist's soul has been bared. As an example I offer "Blessed State," Plate 1.
 
Claiming self-expression purely through formal logic obviously involves massive constraints on what constitutes successful practice and an acceptable result in the artistic process. Yet another significant set of constraints is generated by the requirement that the works be representational. Abstract expressionism is an honored aesthetic in its own right, and formal systems and the computer can be--and have been--used in this context. But the requirement of literal realism in formal imagery spawns a host of problems and concerns that are only starting to be addressed, primarily in the research literature of computer graphics. Representationalism in synthetic imagery remains, in general, an open problem.
 
Many of the problems of generating realistic looking synthetic imagery have been solved, albeit sometimes in ad hoc ways; many such problems yet await satisfactory solution. For example, specular reflection from glossy surfaces has been handled to nearly everyone's satisfaction by ray tracing; however, general realistic lighting models--including atmospheric scattering of light and interreflection between semi-glossy surfaces--are still under active development. In short, there are some things we can do very well with the current techniques of computer graphics; others that are imminently doable but not yet done; and some which are, and are expected to remain, refractory. As an active researcher in the field of computer graphics, I am involved in the effort to move more phenomena from the category of "doable" to that of "done. "As a result, my own artworks more often than not serve simultaneously as a form of aesthetic self-expression and as illustrations of techniques new to the field of computer graphics. This adds a dimension of technical significance to the works; however, I generally intend this to be transparent to the uninformed observer.
 
In fact, one of my key intentions as an artist is to keep this entire esoteric process that I am describing transparent, to make it invisible to the viewer. There are a variety of reasons for this: First, I do not wish to immediately and automatically invoke the instinctive fear of mathematics that the average person is prone to feeling (myself included). Second, it is a research goal to have the image look as natural, i. e. , non-computer generated, as possible; thus the formal process should be thoroughly sublimated in the result. Third, and most important, is that it would be no better than arrogant and obfuscatory to require the audience to confront and grapple with these issues--the images should be able to stand on their own as aesthetic visual statements, outside of this technical context. I say: "Let them, or let them fail. "

1. 3. Deterministic Formalism and the Creative Process

An artist requires constraints, if for no other reason than to narrow down the "search space" (to put it in computer science terminology) wherein the desired result is sought. The formal logic approach certainly provides a rigorous set of constraints on the creative process. It also provides some interesting side-effects.
The determinism of the logic involved means that the result is reproducible: repeated runs of the same program with the same input provide, modulo the occasional hardware glitch, precisely the same output. The artwork is reproduced exactly.  (Or at least the numerical metarepresentation of it is; more on this later. ) This is true despite the fact that randomness is an essential element in all my images--the randomness employed is a deterministic randomness; it is not "truly" random, but what we computer scientists refer to as "pseudo-random. " [3] Pseudo-random processes are simple yet sophisticated constructions from the mathematical discipline of number theory that are, for practical purposes, fully random (i. e. , they lack discernible order or structure) yet which are simultaneously fully deterministic and therefore exactly reproducible.
 
The fact that I constrain my artworks to be purely the output of a computer program insures that they feature this peculiar reproducibility. This could never be true of a painting, for instance, as a brush stroke is not an exactly reproducible act, on the microscopic scale at least. In the case of a computation the result is a string or, at the lowest level, a number or sequence of numbers or digits. This string or number can be checked character by character, digit by digit, for exact fidelity; there is no ambiguity or latitude for imprecision in the representation. Viewed in the light of computational result as artwork, and artwork as representational self-expression, this determinism and exact reproducibility are rather bizarre.
 
2. Distinguishing the Process
 
It is worthwhile to take a little time to point out what distinguishes this process from the more traditional practices of fine arts such as painting, sculpture and photography.

2. 1. Dimensionality

The product of this process is a two-dimensional image; this characteristic it shares with painting and photography. Like a painter or photographer, the artist is responsible for choosing an interesting point of view and framing for the image. As with a camera, a geometrically precise projection of the three-dimensional world onto the image plane is performed; painters have much greater latitude here. Like a photographer, one is free to roam the three-dimensional world, even to employ cinematography to add motion in a temporal exploration.
 
In this new process, though, the artist is responsible for the creation of the entire world being imaged: there are no preexisting objects "out there to be found" and creatively imaged; all objects and all interesting visual detail must be created explicitly. The elegant means we have for creating such visual complexity are at the heart of what makes this process successful and interesting.

2. 2.  Visual Complexity: Fractal Models

Fractal geometry [7] is the key to generating potentially unlimited visual complexity in my work, and in computer graphics in general. Fractal geometry is a language of shape, similar to the language of planes, circles, spheres, triangles, cones and cylinders of the more familiar Euclidean geometry. But as Benoit Mandelbrot has observed [7]:
 
Clouds are not spheres, mountains are not cones, coastlines are not circles, and bark is not smooth, nor does lightening travel in a straight line. . . 
The vocabulary of shape of fractal geometry provides, can describe such complex natural shapes with striking elegance.
 
There are two key aspects to fractal descriptions of natural forms: self-similarity, or the repetition of similar shapes at different scales, and randomness in the model. The first means that we need only describe one fundamental shape plus the relationship of its manifestation to the scale at which it is manifest--a very simple description indeed, for an object of potentially unlimited complexity. (The complexity is simply a function of the number of different scales at which we manifest the basic shape; the shape itself is typically simple, e. g. , a triangle or a sine wave. )  The second aspect, randomness, is the key to having the resulting shapes look natural, rather than man-made or (worse still) computer-made. Control then takes the form of shaping statistical distributions in random processes, rather than explicit specification of exact form. Thus we exchange exact control over form, for power in automatic generation of complex shapes. [2]

2. 3.  Purity of Algorithmic Process

Of course, I could employ my omnipotent powers in this synthetic universe to intervene and make specific, local changes wherever I saw fit. In adherence to a self-imposed constraint of process, however, I do not allow myself to do this. This often proscribes the shortest route to a desired result (as in obtaining a desired hue in a given highlight) by disallowing local intrusions and modifications to the world or the image that would, in practice, be relatively easy to execute. What is gained in exchange, however, is purity of algorithmic process. Creation of an image becomes a dance with the opportunities and serendipity granted by the powerful, random fractal models that I create, embellish and (more or less) control. By disallowing post-process meddling with the results of various algorithmic processes I employ, I gain two compelling benefits: legitimacy in illustrating the descriptive power of these abstract fractal models, and claim to an elegance in the creative process--the image is indeed a theorem proved, in one pass, in a formal system. [4]
 
Adherence to principles of algorithmic purity legitimizes one of the key claims I make about the significance of this process: that it entrains the intellectual depth of logic, mathematics and computer science as its foundations. In practice, it entails the pure use of formal logic to obtain the desired result. If I were to indulge in local meddling, this claim would be compromised and/or invalidated.
 
Again, another (more or less arbitrary) constraint I impose upon the process is that the results represent self-expression. Expressionism is a practice the popularity of which perhaps waxes and wanes through the history of the fine arts; I do not claim that it makes my work in any way "better," I only note that it constitutes a significant constraint upon what I, as an artist, consider to be a successful result.

2. 4.  Proceduralism

These concerns lead us to proceduralism. [2,12] Proceduralism is the practice of abstracting complex behaviors into relatively terse functions or algorithms that do not contain specific information about details of the phenomenon, but rather encode a given behavior in a formal set of instructions that specify the behavior everywhere it might manifest itself, and which may be evaluated only when and where such information is desired (what we charmingly call "lazy evaluation" in computer science).
 
Thus, in the procedural approach, a "virtual world" is abstracted into a compact procedure or set of procedures. These procedures are in turn controlled by a relatively few parameters which affect (only) global control. Alvy Ray Smith [15] called this database amplification; I refer to the process of creating landscape images within this paradigm "playing God in a found Universe"--I may have God-like powers over these worlds, but in practice, because of the randomness they embody, they behave as if they have a will of their own. Furthermore, they have an ineffable sense of having existed a priori; of somehow being inherent in the timeless, universal formal procedures that specify them and of always having existed there as an aspect of Nature, or at least of Mathematics, just waiting to be discovered. As an artist, I simply interpret these forms visually. Thus they may represent, at least in part, "found art." But there nevertheless remains enormous latitude for the exercise of aesthetic judgment in the development of any given image. It is, after all, but one out of an unimaginably huge, if finite, multitude of images that might have been selected (more on this later).

2. 4. 1 Functions and Algorithms

Proceduralism in practice consists of devising functions which in turn are implemented as algorithms, or unambiguous sequences of instructions telling the computer exactly what to do, for a given input. Functions are a mathematical concept. They may be viewed very simply as contraptions that change values given as input, to other values--the output. The input and output values might be very different: input may be numbers and output colors, or other stranger and more subtle mappings.
 
Mathematically, we refer to the action of a function f like this:
f:D->R which simply says that function f sends (maps) input values from D (the domain) to values in R (the range). It is useful to distinguish the set of possible input values D from the set of possible output values R as they may be quite different kinds of things.

The simplest kind of function is a scalar valued function of a single variable, denoted f(x) = y.  (We use lower case letters to refer to specific values, upper case to refer to the entire set from which those values may be chosen. )  A scalar value is just a single number. A function of one variable has only one input value.

Most interesting functions are the more complex vector valued functions of several variables, denoted f(x1, x2, Ö, xn) = [y1, y2, Ö, ym]. This particular function takes a number (n) of input values, and maps them to another number (m) of output values. Such functions are more common in my images. They typically take more than three values as input: the three spatial coordinates of the location where the function is being evaluated (as the function is usually defined over all of space) plus a set of variables controlling the behavior of the function. They output some small number of values, such as the primary color components of a certain color and a spatial vector used to modify the apparent orientation of a surface (as with the water in Plate 1).

It is the concoction of functions like this with interesting visual behaviors, which constitutes the first step in this formal creative process. These functions are small parts of a much larger program that orchestrates the overall creation of the picture. Examples of such functions in action can be seen in the ripples in the water in Plate 1, as well as in the roughness of the moon and the coloring of the mountains. Each of these effects issues entirely from the functions evaluated on the surfaces there. (Believe it or not, the water is a perfectly flat plane, and the moon is a perfectly smooth sphere!)  The fact that the functions are defined over all of space allows us to evaluate them anywhere we desire. Thus the moon is carved out of an infinite block of "moon-ness," the mountains out of an infinite virtual block of snow, rock and greenery, and the water out of an infinite expanse of abstract "sea. "

2. 4. 2 Global Parametric Control

The values xi (i denoting the numbers 1 through n) which serve as input to our functions are known as parameters. The parameters beyond the three spatial coordinates at which the function is being evaluated, are used to determine the overall behavior of the function. The way these functions are usually constructed, the parameter values affect the function's output everywhere in space. This amounts to global parametric control of the function's behavior.

In practice this means that, for instance, I may exactly specify a color for a light source; if I dislike the resulting hue in a particular highlight (a local effect) I may change the color of the light source accordingly, but this changes tones everywhere that light falls in the scene. Similarly, if I dislike the shape or location of a given wave in the water or mountain peak in the terrain, I may change it, but this change will also affect all other waves or peaks and valleys. The randomness at the heart of the fractal models I use grants both enormous flexibility and expressive power, but it also entails complete abdication of control over specific details in relation to their global context.  While this global parametric control represents a profound creative constraint, it also entails an enormous (and often elegant) simplification of the final stage in the creation of the image: After the program is written, all that is to be done is to select values for these parameters.

2. 5. Representationalism and Conceptualism

When manual renderings were the only source of pictures, artists were deeply concerned with accurate representation; they developed a full set of techniques for realistic rendering. Since the invention of the camera, representationalism has not generally been a vital issue in the visual arts. Our new process, however, reopens the problem of representationalism: We simply do not yet know, in general, how to reproduce the visual appearance and complexity of the everyday world in computer synthesized imagery. It may thus push us back several steps in the cycle of aesthetic evolution (or is it simply forward, one step?)

Recently, conceptualism has sometimes given the ideas behind an artwork work precedence over the artwork's physical manifestation. For that reason, I wish to emphasize throughout this essay the depth of the conceptualism inherent in this process, and to cast a faint glimmer of light into those depths.

2. 6.  Lighting

The artist's responsibility for lighting in synthetic scenes brings this process into relation with lighting as used for photography and stage performances. Direct responsibility for lighting is something new for landscape rendering, where artists have traditionally relied on serendipity in Nature to provide striking effects. As the author of a synthetic world, we will find nothing that we do not explicitly create. And of course, due to the nascence of the process, we have yet to approach the kinds of diverse, subtle and spectacular effects captured by the masters of more mature art forms like Bierstadt, Monet, Turner and Adams.

The process of providing synthetic lighting is exactly analogous to stage lighting. We have light sources with color, brightness, direction, and area of influence. We can position those lights wherever we want. We can have as many of them as we like (though in practice I rarely use more than two--a warm sunlight and a cool skylight). In addition, we are responsible for specifying, mathematically, the interaction of light with surfaces in the scene: are those surfaces mirror like, glossy, or matte?  Or something different, perhaps completely unnatural?  There are no set limits here. This mathematical treatment of light and color also marks a new practice in the visual arts; we will expand upon it later.

2. 7.  A Model of the Creative Process

A particularly fascinating view of the parametrically controlled creative process is that of searching n-space for local maxima of an aesthetic gradient. Let me explain: We have created a procedural, parametrically-controlled model of a synthetic microcosm. Say there are n independent parameters in that model and the specification of its projection onto the image plane. As these parameters are independent, we can think of each as representing a degree of freedom, or an additional dimension or direction in which we may move. Taken together, the n parameters define an n-dimensional space or n-space for short. In this space we are free to move not just up and down, right and left, or forward and back, but in a whole lot of other abstract directions as well. This may seem abstruse to the layperson, but mathematicians, scientists and engineers never hesitate to work in spaces with many more dimensions than the familiar three of our everyday world.

The task of the artist then is first to create these n parameters (n being usually around two to five hundred in my own images) and their (deterministic) meaning through creating the procedures or functions that they drive, then to "tweak" the values of these parameters to obtain a satisfactory result or image. The creation of the parameters in formulating the formal system corresponds to defining the n-space; the process of refining the parameter values, or choosing the axioms to start with, corresponds to searching that n-space for local maxima of an aesthetic gradient. A local maximum is location in the space from which all directions lead "downhill," that is, it is a kind of hilltop in n-space. "Downhill" is defined by the aesthetic gradient function--the completely subjective (non-deterministic) assessment on the part of the artist of what constitutes a "better" image, in terms of the parameter values. Obviously, this so-called "function" is not unambiguous: Its value will depend on the criterion by which the image is being assessed, and even upon the mood of the artist at the moment of evaluation. [5] The local maximum is then a point in n-space from which a small move in any direction would result in a "less good" image.

Ambiguity notwithstanding, this n-space gradient ascent model is more than just entertaining: It points out that a given image represents merely a local maximum of the aesthetic gradient field. Other, more global maxima ("higher hilltops," corresponding to "better" pictures or possibly "better" self-expression) undoubtedly exist elsewhere in the rich abstract n-space of potential images defined by the formal system. This is very much akin to noting that a photographer might have gotten a better shot by choosing a different vantage point or time, except that we have much, much more control here. Creating and searching this n-space is, I submit, a singular way of obtaining self-expression.

2. 7. 1  Searching N-Space for Aesthetic Maxima

What does this process look like, in practice?  I have a bunch of numbers, usually about two to five hundred, which define the entire scene I'm creating (other than the landscape itself, which consists of thousands of numbers that, again, I don't allow myself to change or fiddle with). This is a lot of numbers to deal with. And it turns out that if you change more than one or two at a time, the effects are usually conflated, and you can't be sure which change accomplished what effect. Thus I spend long hours massaging the values one or two at a time, until I am sufficiently satisfied or exhausted to "call it a picture."

This is a very tedious process. It is also very obscure: No one else can hope to use my programs--the meanings of the parameters are simply too obscure for another artist to practically deal with. In fact, I am only really cognizant of their intended effects when I create the functions; this intent is quickly forgotten in the complexities of my work and daily life. If later I need to reconstruct that meaning, I generally have to go back and look at the computer code that I've written to implement the functions, and figure it out by inspection, reverse engineering, and the memories of my original intent that the inspection triggers.

This is not a highly desirable interface or working methodology. When people ask me "Can other people use your programs, too?" I have to answer "No." (I certainly lack the time and patience to explain or document all of these things. ) This deplorable state of affairs I would attribute to the youth of the method--it is certain to be improved over time. Powerful mathematical methods can be brought to bear in such endeavors. Principle components analysis may be used, for instance, to reduce the dimensionality of the parameter space, and to maximize the effects of changes in parameter values (though the resulting reorientation of parameter vectors in n-space may destroy any original intuition as to parameter meaning).

2. 7. 2  Genetic Programming

One very promising method for managing the creation and search of the high dimensional parameter space is genetic programming. In the genetic approach, we borrow some concepts from biology, namely genotype, phenotype, mutation, and sexual reproduction. Genotype is the encoding of an organism's form in its DNA, while phenotype is the physical manifestation of that coded form in an actual organism. Mutation is the spontaneous change in the encoding itself, and sexual reproduction is the recombination of genotype information from two individuals, by "mixing and matching" parts of their genetic code. This is a powerful approach to creation--after all, it appears to have gotten us to where we are today, as intelligent sentient beings.

Richard Dawkins popularized the genetic approach in his book "The Blind Watchmaker." [1] Several artists are using genetic algorithms to create striking works (though they are not representational, in the sense that I am using here). Karl Sims creates wonderful abstract images very rapidly with his genetic software, running on a massively parallel supercomputer. [14] My personal experience with his system showed it be an astonishingly fecund process. And it is as simple as can be: The computer puts up a sequence of images, you pick one you like which the computer then proceeds to mutate for you, or you pick two which the computer then "breeds" for your pleasure. Mutation is random, and "natural" and sexual selection are performed by you, the user. William Latham uses similar genetic methods in creating his fantastic sculptural forms of Cambrian beasts that never were. [16]

While this genetic approach to the management of procedural models is incredibly promising, it is currently limited to the creation of such free-form objects and images as Latham's and Sims'. Indeed, one of the points that Dawkins stresses is that evolution (of life on Earth) never has any goals as such. Rather, its only "values" are propagation and persistence; organisms satisfying those two criteria are "successful," those which do not are "failures." Unfortunately, it is therefore not immediately apparent how to apply the genetic methods of selection and random mutation to the evolution of models of non-biological natural phenomena or, more generally, to the problem of converging on any highly specific and complex a priori goal.

2. 7. 3  A Biological Analogue

Roman Verostko [17] has likened software that embodies an artist's aesthetic judgment to the genotype, and the resulting artwork to the phenotype. Program execution then corresponds to epigenesis, the biological process of the development of an undifferentiated cell, as a spore or an egg, into a complex organism.

The work of Verostko, Sims, Rooke and others is closely related to the process I am describing here; we may be regarded as being of the same school of algorithmic art. Yet our processes are not identical. Verostko's "Hodos" system has a deterministic front end: the computer driving the plotter. The back end, the plotter, is no more deterministic than any paintbrush. As a result, none of the phenotypes is exactly reproducible (not that that is a desired trait, it is simply a distinction between the processes). The main distinction between Verostko's process and the one I am describing is that Hodos creates an artwork, while my process creates only a metarepresentation (again, more on this later). In this sense, Hodos is more mature and complete; as we will see, our new process as yet lacks a satisfactory medium in which to manifest the final piece.

3.  What the Process Is Not

To further distinguish the process, it is worthwhile to point out certain aspects of what the process is not, to clarify by defining the negative space around it.

3. 1.   A 2-D Canvas

One thing this process is not, is a flat canvas. While the final image is indeed two dimensional, its creation takes place in three dimensions (excluding time). We are responsible for the creation of an entire three dimensional world, which we proceed to image by projecting it onto a film plane like a photographer, only doing so with mathematics. [6] The potential of the process will be expanded when we gain the capability of rendering scenes at video frame rates--then the viewer will no longer need be passive, but will be able to enter the synthetic world and explore it, much as one moves about to inspect a piece of sculpture or a physical environment. In an immersive VR environment, this is foreseen to be quite an exciting development, though one better suited to entertainment than art, perhaps.

It is important to me, as an artist, to emphasize a certain point: The really interesting uses of the computer in the creation of artworks will not be in the traditional role of a canvas and paintbrush. Certainly, the computer can function as such and offers some unique capabilities, such as infinite erasure and reworking capabilities, not possible with paints. But that does not mark a significant conceptual breakthrough, merely incremental progress for an established process. Not that there is anything wrong with using the computer in this way--most of the best computer art has been, and will continue to be, produced in this way. I simply wish to emphasize that the process I am describing has very little in common with that, aside from using some common hardware devices and their common aesthetic disciplines of composition, color usage, and so forth. The means of creation are utterly different, and it is only the new process that is truly significant as an intellectual event in the history of art, I maintain.

3. 2.  Local Control

Almost every established process in the visual arts involves local control: details are manipulated in isolation from the whole. Any given brush stroke, for instance, while it certainly may indirectly affect, and be indirectly affected by, its global context, represents an absolutely local act. It does not directly affect anything beyond the area where the paint is applied.

Changing a global parameter, in contrast, immediately and directly affects everything, everywhere its function has influence. Thus I again wish to emphasize the contrast with, for instance, painting and sculpture, where the work is usually realized incrementally by a series of fundamentally local actions. When working with global control only, we have a much less precise control over details, but gain in return something akin to the power of "painting with a broad brush"--we cover a lot of territory with a single action.

3. 3.  "Of the Hand"

As the only access to expression is through the formal logic of the computer program, there is no "evidence of the hand" in the final work (or if there appears to be, it is illusory). Some may find this anathema, but it is important to point it out as a distinction of the process. The mechanism of creation that I use is extraordinarily abstract and removed from the product. This is part of what is interesting and bizarre about the process: that such prosaic imagery comes about through such indirection and abstraction. I claim that this is significant in itself.

3. 4.  Pure Mathematics

I am often mistaken for a mathematician. That I am not. While all the models employed are based on logic, and many are mathematical models of natural phenomena, the mathematics I employ is generally quite simple compared to what a "real" research mathematician would be involved with.

Pure mathematics, after all, assiduously shuns applications and other associations with "reality." And what I am up to, is recreating reality as we see it.

3. 5.  Computer as Creator

Finally, and most importantly, this process does not represent creative action on the part of the computer. A computer, given no instructions, will just sit there dumb as a rock, if a little warmer. A computer (on a good day) will cheerfully do exactly what you tell it to do, with blinding speed and precision. It will never do anything useful that you, the human operator, did not describe explicitly and in excruciating detail precisely how to do (this is the tedious art of computer programming). Remember: the computer operates as a formal system, and that admits no ambiguity and no choice, only deterministic cut and dried yes or no instructions and conditionals. Certainly, the complexity of the instructions we hand the computer rapidly surpasses our human ability to track every detail thereof, while the computer never loses track of one iota. But the computer remains a simpleton; a very fast and capable simpleton, but a simpleton nevertheless. If we puny humans were given eons of time and inhuman patience, we could track, produce, and reproduce every tiny detail of what the computer does--only we'd make a lot more mistakes along the way.

The point is, the computer acts as a powerful tool, maybe even like a semi-intelligent slave/apprentice in practice, but is in no way the creator, the author of the product. It simply did as it was manipulated to do, as with a paintbrush in the hand of a painter. The main difference is that the form of the manipulation is highly abstract and rigorous, and very different from the physical manipulation of tangible media that we are more familiar with in the visual arts.

4.  The Process in Action

How does one proceed to create an image through this process?  First, we have to posit an abstract model of a world; then we must map that model into a formal system--a computer program. Next we devise axioms, or input to the program. Finally, we run the program to create the output, which we will interpret as an image. This output is, like the input, in the form of a string of symbols or values (i. e. , numbers; ones and zeros). Such a string is hardly an image; therefore we call this the metarepresentation of the image. This metarepresentation still requires a considerable array of sophisticated machinery and methodology of interpretation, to translate it into the intended image.

We can then further subdivide the process of image creation into two separate undertakings: creating the metarepresentation and interpreting it. This essay concerns itself primarily with the first; it is here that the bulk of the intellectual content resides. The second represents primarily an engineering problem, though there is a considerable dose of color science involved and that is none too simple in itself. [19]  In artistic terms, these two parts correspond to process and medium: the first concerns itself with the machinations of artistic creation while the second is about producing a physical manifestation. After the first part is done, all we have generated is a still highly abstract and intangible form. It is the second step that maps this abstraction into something that can be perceived in a sensible way, and maybe even felt, held, or hung on a wall. It is interesting that the two, process and medium, are so neatly partitioned in this new way of working.

4. 1.  Creating a Metarepresentation

Again, the first phase is the creation of the metarepresentation: the theorem, the string, the sequence of digits, the one huge number, the signature on a magnetic or optical storage medium, or the image file; however you care to view it.

4. 1. 1  Creating the Formal System

We begin the process unconsciously as a young child: observing and cataloging sights, phenomena, and behaviors in Nature. Over time we build some potent and internally consistent models of Nature and the behavior and visual manifestations of phenomena there: clouds, mountains, water, light and color, to name but a few. Some training in the sciences teaches us the practice of mapping this intuition into formal, mathematical models of the behavior of natural systems, and the practice of empirical testing and verification of those models. We become familiar with many such formal models that scientists before us have devised and refined, and we learn where to find descriptions of such models--in the scientific literature. Becoming a practitioner of computer graphics, we learn the practice of mapping such models into formal systems that the computer can efficiently use to generate pictures. Note the qualification "efficiently," as the scientific literature consists mainly of picayune and non-general models, along with some very elegant and general ones that are simply not well suited to the practice of image synthesis: Witness the wave model of light. This is a potent, elegant model of Nature that the computer just can't practically deal with for image synthesis, as it involves too much complex calculation. What we require are models with potent descriptive capabilities, which also admit to reasonable computational implementations.

It is this formulation of a model of Nature and its mapping it into a computer program that constitutes the first phase of the process. It is in the act of creating the functions, in the writing of the program, that we create the parameters and give them their functional "meaning" (the program semantics). The program, again, represents the rules of production in the formal system, which will be repeatedly applied to the axioms, or the input, in the process of deriving the theorem that is the result or image metarepresentation.

Our tools at this stage are such abstractions as shaping functions, e. g. , polynomials with continuity in a desired number of derivatives, numerical integration methods, logic in the form of conditional "if/then" statements, and algebra as applied to color (more on that later). Largely by combination and recombination of a series of standard building blocks, such as fractal functions, bump maps, color maps, etc. , we construct a relatively small set of functions with which we intend to generate a world, and the given image of that world.

The process of generating the formal system is so involving that, in practice, almost all of my own images have come about as verifications of some abstract idea that I was attempting to map into such a system. In this sense they represent illustration of the model being developed; I use the word "illustration" deliberately, despite the stigma that may be attached to it in the visual arts. Keep in mind that in our new paradigm, representationalism is no longer a "pedestrian concern"--it is again an unsolved problem, and we are actively working towards solving it. Thus the work cannot be dismissed as "mere illustration" or "simply representational"; these are highly honorable labels in our context. This may mark an inversion of contemporary thinking in the visual arts.

There is one inevitable and undesirable side effect of this stage of the process: parameter proliferation. In the process of developing a potent model of complex phenomena, we almost always end up introducing a large number of parameters that control the behavior of our models or functions. This means that the artist will be faced with a bewildering array of values which must be fixed, to create an image, and refined, to create an artwork. Again, we currently know of no way around this, but that may just be another symptom of the youth of our endeavor.

4. 1. 2  Generating Axioms

The next step is to formulate values for those multifarious parameters. This is not quite as bleak a prospect as it may sound, as the same intuition that drove the formulation of the model and the functions, also informs the choice of values for the parameters. Thus we are not groping in complete darkness; we generally have a good idea of where to start and how to change the values to obtain the desired effects.

Nevertheless, as described before, fixing these values is a long and tedious process in practice. The goal is the creation of an input file, to be fed to the program upon its execution, which in turn results in an image. The process in practice consists of sitting in front of a terminal, working in a text editor to change the strings in the input file, running the program with the modified file, inspecting the results, going back into the editor to make changes, running again, and so forth. I generally spend the equivalent of about two to six weeks of full time work in this loop, for each of my finished images.

But it is important to note that the procedure isn't quite as neat and sequential as I've presented it to be so far. These first two stages are not really so distinct--while I am refining the parameters to the functions, I am generally simultaneously developing, extending and refining the functions themselves. Since the ultimate theorem proved is determined by both the axioms and the rules of production, we naturally massage both the axioms and the rules more or less simultaneously as we develop that theorem into the image we desire. Furthermore, even the author of the formal system would not generally care to be confronted with the need to explicitly specify every single parametric value in the model in the input file--there are simply too many hundreds of them. For this reason, many of the axiomatic values are hard coded as constants in the program and thus are not part of the input file. (This constitutes poor programming practice, from a computer science standpoint, but is nevertheless necessary from a practical, user's standpoint. )  Thus the separation of axioms into input and rules of production into program is not very precise. It would actually be easy to be very thorough about so partitioning the system, but in practice it is neither necessary nor desirable.

4. 1. 3  Deriving the Theorem: Epigenesis

Once we have a set of production rules and axioms--a complete formal system--we may proceed to derive a theorem, to create an image. Again, this means firing up the program and running it with the given input file. Execution time for the program varies widely for my own images, from a minimum of about a minute to a maximum of several weeks. This at a rate of tens or hundreds of millions of operations per second [7]--there are obviously many, many steps in the derivation of the theorem, far more than any human being could ever hope to perform or even follow.

Again, each of these operations (other than, perhaps, memory accesses) represents a transformation to a string: One sequence of ones and zeros is translated, deterministically, into another. The sum total transformation is that of translating the input file into an image, an image that may represent self-expression in an artwork to the person orchestrating the execution of the program.

The formal system embodies the aesthetic judgment of the artist; those judgments are implicit in its construction. Execution of the program, derivation of the theorem, corresponds to the epigenesis discussed by Verostko [17] and Waddington. [18]  A successful result reflects the artist's aesthetic judgment and may represent self-expression for the artist, derived through deterministic mechanism. Again, this juxtaposition of determinism and free will is at the heart of what makes the process interesting, from a philosophical standpoint. Determinism ultimately precludes free will, yet here it is used as the vehicle of expressing free will and the latitude for expression of individual judgment which free will grants.

4. 1. 4  The Loop of Scientific Discovery

Gregory Nielson points out [11] that this process embodies the basic loop of scientific discovery: One posits a formal model, observes the behavior of the model in comparison to Nature, then refines the model and makes further observations, proceeding in an iterative loop. Perhaps the main difference between mainstream science and this practice in computer graphics, is the time required for a single iteration of the loop: For a scientist, it may be decades, even a lifetime or longer, whereas in computer graphics it is typically measured in minutes.

4. 1. 5  The Role of Intuition

Both science and art are ultimately driven by intuition. No scientist derives potent models of Nature through exhaustive search of all the possibilities provided by first principles. Neither does any mathematician originally get to the proof a hard theorem by simple extrapolation of logical principles. Rather, they both retrofit their (originally) intuitive conjectures with a deterministic logical derivation to advance them to the state of logical conclusions. These logical derivations then become what both mathematics and the physical sciences base their clams of irrefutable legitimacy upon. And indeed, when well-formed, these arguments are (logically) irrefutable and because of this, when they are fully comprehended they may have a truly compelling and seductive character of somehow reifying, or at least reflecting, the self-evident design of the universe. [8] But if not for the role of intuition in positing the original conjecture and in formulating the logical derivation, computers would immediately leave us all in the dust, intellectually, because we could program them to do the same far faster and more accurately than we humans. Curiously, though--and to the great detriment of the field of "artificial intelligence"--it turns out that, ultimate expositions in deterministic proof notwithstanding, no mathematician or scientist can explain exactly how they originally conjectured the result, or even how they arrived at the formal derivation finally presented. No, in the creative process scientists, mathematicians, and artists all rely on intuition to the same degree and in exactly the same way. It is in only aspects of their final respective products that they so differ: Scientists' and mathematicians' final product is the logical edifice itself; the artist's final product is a physical object or temporal event,. the accurate apprehension of which is often highly dependent on dynamic intangibilities such as cultural context.

The point is, none of us knows precisely how to get where we want to go a priori, but we all conjecture worthwhile goals and eventually intuit some path that indeed gets us to our desired ends. Such is the magic of human intelligence, and this is what continues to distinguish us from any "artificial intelligence" yet devised.

4. 1. 6  The Role of Serendipity

Finally, we must note the role of serendipity in this formal process. The fact is, we don't always know exactly what the results of our derivations will be, and we can't realistically expect to always be able to accurately foresee the behavior of our deterministic models (the emerging science of chaos is making that abundantly clear).

Serendipity emerges from the unforeseeable, as with random models; from the unforeseen, as with a model that has not yet been subjected to thorough intellectual scrutiny; and from errors and mistakes, as with typos and program bugs. Each of these factors has played an important role in the genesis of my own images. Plate 1, for example, did not come from a preconceived idea for a visual composition. Rather it came from the unforeseen, or a sort of bug: I had moved the program that I expected to generate a thoroughly familiar mountain range, to another computer. This new computer had a different random number generator, which I had not foreseen in writing and porting my program. Thus when I ran the program I was confronted with a wholly unexpected landscape, which serendipitously harmonized with the large moon I had put in the sky, but not yet scaled own to a reasonable size. Perhaps every artist can tell similar tales, but here it is important to see that, though we work through a formal, deterministic process we are still in an intimate dance with chance, the unknown, and the unpredictable.

4. 2.  Interpreting the Metarepresentation

As I said before, the theorem we derive is nothing more than a string of symbols in the computer's memory. Nothing tangible or image-like about that, yet. But we do intend an image, and we have (thankfully) a preexisting machinery of interpretation for that metarepresentation. I will now outline that machinery, and sketch how that machinery is currently woefully inadequate to the creation of works of art. This, too, is a symptom of immaturity of the process and medium, and will change for the better with time.

The problem at hand is how to map the formal metarepresentation, i. e. , the string or sequence of numbers, to a certain appearance in a physical manifestation. Obviously, we have enormous latitude in this transformation, as the metarepresentation has no intrinsic meaning: It is merely the deterministic result of applying a series of abstract transformations to some input symbols; there is no meaning in that other than what we (more or less arbitrarily) ascribe to it. [9]  Also obviously, we always had a certain interpretation in mind for the result, throughout the process.

Unfortunately, when we leave the idealized, uncertainty-free world of formal logic and its embodiment in the computer to enter the "meat" world of physical manifestations, we lose the grace and precision of Boolean digital representation and enter the fickle, imprecise, and heinously ill-defined world of things analog, physical, and continuous. The real, "analog" world is far less well behaved than the formal and deterministic world in which have been dwelling. We face a whole new, different, and largely unrelated set of problems, problems usually without the clean, irrefutable solutions we've been using. This is the world of color monitors, color printers, and photographic reproduction. This is where we do well to hand our theorem over to the artisans skilled in working with such things, and beg, cajole, plead with and threaten them to do our bidding.

Such is the real world, with which our abstract idealizations must eventually interface.

4. 2. 1  Numbers as Colors

We have a huge string, usually of hundreds of millions of symbols, or megabytes of data, which we wish to interpret as a picture. "How?" one might ask. Well, again fortunately, there are conventions for this interpretation that we can follow to make our lives easier.

The primary convention is to regard the string as a sequence of numbers, usually comprised of eight 0/1 symbols or digits each. Such an eight bit string can, by logical and mathematical convention, encode a single number between 0 and 255, inclusive (those 256 values correspond to the 28 possible distinct combinations of eight ones and zeros). According to the tristimulus [6] model of human vision, we can encode all perceptible colors into combinations of exactly three primary colors. [10] By more or less arbitrary convention, we may interpret our string of eight bit numbers as representing consecutive triplets of eight bit values for those primary colors. Thus we know what the derived string "means": It is a sequence of color values for pixels (pixels being the atomic colored dots of which our final image is composed). These color values proceed in a canonical order, as do the pixels they are meant to represent. (There is a wide variety of standard digital image file formats which specify the actual form and sequence of data elements, such as GIF, TIFF, TARGA, etc. , but they all simply represent different conventions for encodings of the same information. )

This interpretation is arbitrary, but then so is any interpretation of an intrinsically meaningless formalism. By being as specific as we can be about the intended meaning or interpretation of the metarepresentation, we take on another arbitrary set of constraints that greatly simplify our task.

4. 2. 2  The Finite Number of Possible Outcomes

As each pixel is represented by three eight bit numbers, it can have exactly one of 28 x 28 x 28 = 224 = 16 million values. If we have, say, 220 = 1 million pixels in the image then the entire image can take on exactly one of 224 x 220 = 244 values. While 244 is a very large number, it is finite. Thus, at a given number of pixels (or image resolution) and a given number of possible colors, there is a large but finite number of pictures that can be represented. [11] The actual number will be considerably less than 244, of course, as no human observer would be able to distinguish between the different visual representations of many slightly different metarepresentations.

We can then view our elaborate logical formalisms and derivations as simply selectors that choose for one out of a truly vast, but finite, set of possible outcomes. That this set exists, perfectly defined a priori, adds to the sense that this is all "found art" that exists, and always has existed, in the immutable formalism of that predefined set. The simplicity of the definition of that set--as all possible combinations of 244 ones and zeros--is part of the compelling beauty of the mathematical logic that underlies the artistic processes we are illuminating here.

4. 2. 3  Additive vs. Subtractive Color

Another factor that distinguishes working with the computer from most other visual media, is that we work in an additive colorspace, versus the more familiar subtractive colors. The difference is that when using pigments, one is subtracting color energy out of the impinging light that illuminates the work. If there is no illumination there is no visible work, and presumably the optimum illuminant is white light, as it contains all the colors in equal proportions to start with. In the subtractive model, a red pigment absorbs the green and blue energy in a white illuminant, and reflects the red.

In computer graphics, we start with a dark (optimally, black) surface, and add in the color energy we desire. Thus a red area is simply made to emit red light, and the work is visible in complete darkness (and conversely, may be hard to see clearly in a brightly lit environment). This convention came about because the standard output device for computer graphics is a television monitor, as opposed to a canvas or sheet of paper.

The main difference between additive and subtractive color, is that the primary colors of the two systems are complementary. In subtractive color (contrary to what you were taught in grade school), the primaries are magenta, yellow and cyan. In additive color, they are red, green, and blue. Thus, for instance, in additive color we must learn to think of yellow as a sum of red and green (not immediately obvious), and brown as a dim version of a reddish orange.
We also find that images developed on the luminous monitor may not be nearly so striking when mapped to a subtractive medium. Plate 1 is one of the few examples in my own experience, that looks fairly good in both media--though there is a magical luminous quality on the monitor, which is missing in a reflective print.

There is a hard copy solution to this: back-lit transparencies. Unfortunately, these are quite expensive to produce: The light box alone can cost several hundred dollars (and be ugly to boot) for good-sized print. Back-lit transparencies to have one significant advantage over reflective prints, however: The computer image's inherent lack of surface detail, as in the impasto of a painting, is obscured as one's attention is simply not naturally drawn to the physical surface in a luminous display.

4. 2. 4 Archival Reproduction

Color reproduction from digital data is a difficult problem. It seems unlikely that a television monitor would be accepted as an artwork by collectors or the art consuming public. Monitors are large, heavy, low resolution, and, to face facts squarely, they look big TVs and not like something to hang on your wall. The market is, and will remain for some time to come, for (thin) two-dimensional images on a surface, like a painting or a print; not for four inch deep, ungainly light boxes with dangling power cords, and certainly not for a big, ugly, expensive, high quality video monitors.

Thus we face the problem of making high quality reflective prints of the artworks, which both the artist and the collector can be happy with. Achieving the artist's satisfaction may require a large investment of time and money on the his or her part, to find a printing house to produce such objects. The artist can expect to spend several thousand dollars on this, and what is produced is not generally a one-of-kind object, but a series of prints. This affects the market for the work; it is not like a painting, but more at a lithograph or photographic print series.

The second criterion, making the collector happy, complicates the reproduction problem further. Serious collectors require archival artworks--pieces that can be expected to last 100 years, without significant fading or other such degradation. This rules out color photographic prints, none of which are considered archival. (Gloss Cibachrome prints are considered to be semi-archival, i. e. , they may last about 50 years; no backlit transparency even comes close, due to the high, UV rich light levels in a light box. )  What this leaves us with, at the time of this writing, is four color offset printing. Such prints can be made on acid-free paper, or at very high (400 dot per inch) line screen resolution using carbon pigments on a polyester substrate. The former is the equivalent of a quality lithographic print; the latter is superarchival, with a life expectancy of about 500 years, but is very expensive and constrained to modest physical dimensions.

These problems mean, in practice, that color reproduction is largely an unsolved problem. It is not realistic to expect the artist to be able to sink several thousand dollars into each finished work, as artists are notoriously indigent. Thus I for one consider myself to be, so far, an artist without a product.

4. 2. 5  What is the Product?

Given that there were a product, we face the well known question in computer art: What exactly is the "product"?  Is it an object, such as a color print?  Is it the metarepresentation, the image data?  Is it the formal system?  Or is it the formal system plus its machinery of interpretation, i. e. , the program, the input, and the computer that runs it?

Of all of these possibilities, the only reasonable one is the first: The product is some tangible hard copy object or print. The metarepresentation is not particularly valuable as it is exactly reproducible, due to the determinism of the process that creates it, and because it is so difficult to translate into an art object. The product cannot be the formal system--I have years invested in the program that creates all of my images; I would not sell exclusive rights for its use for any price. And even if I did I am capable, in principle at least, of recreating an exactly equivalent formal system, and indeed upon a sale of this sort I would immediately have to do my best to do exactly that, just to be able to get back to work again. That would no doubt lead to disgruntlement among the collectors of my work. Finally, it is absurd to propose the last option, that the work consists of both the program and the computers that run it: Even if I were to give the software away for free, the hardware cost could reach into six figures and that hardware would have no special value whatsoever to the collector, as the computers I use are always off-the-shelf units, exactly replaceable by the manufacturer. That is, it has absolutely no uniqueness associated with the image--it would be like including the paints, paintbrushes and easel in the sale of a painting; they are of no use to the collector, are generally quite replaceable to the artist, and are of no direct relevance to the finished piece.

4. 2. 6  What Constitutes the Original Work?

A final image is typically rendered at a very high resolution: perhaps three hundred dots per inch, at a final print size of two to four feet on a side. The television monitor on which the images are developed can display at most about two thousand pixels (dots) on the horizontal axis, and typically closer to one thousand. Therefore the image that is sent to the printing device, regardless of what technology or medium that device is based on, is usually of much higher resolution than can ever be previewed--the first preview is of what comes off the press, so to speak. Therefore, given that the product is the final physical print, that print is also the original in a very real and significant sense, as there never existed any visible, full resolution representation or even metarepresentation prior to the final print. This may have consequences to the value of the print, in the eyes of collectors.

5.  Discussion

Let us now briefly discuss the implications of this new process.

5. 1.  What Role Intent and Understanding?

As I have pointed out, the computer can be quite readily be used as a novel canvas, paint, and paintbrush, for use as with prior two-dimensional media for the visual arts. Used that way, the resulting works will be essentially "of the hand," and thus part of the existing continuum of two dimensional media.

When the artwork is algorithmic, issuing directly and unmodified from a formal description, it becomes more interesting. When the algorithm is deterministic, it becomes more interesting still (after all, artists such as Sol Lewitt have produced non-deterministic algorithmic artworks for some time now).

But I maintain that deterministic algorithmic artwork is only truly significant when the artist is also the author of the formal system, and can claim to understand it thoroughly and to have intended (modulo serendipity) to create the result produced. Thus artworks created by someone else using my software would lack conceptual significance, even if they were more aesthetically sophisticated. If Picasso had invented a "Picasso engine," and others used it to create Picasso-like works, these works would simply would not be quite the same as an original Picasso, after all--even if others were able to "improve upon" Picasso.

The artist can only really claim to have accomplished self-expression through formal logic, when he or she authored, for that specific purpose, the formal system through which the expression is obtained.

5. 2.  What of Turnkey Systems?

What then, of turnkey software for creating computer art?  There are many powerful programs becoming available that unlock the substantial potential of the digital medium, and there will continue to be ever more, of greater sophistication, power, and novelty. Programs such as Adobe Illustrator and Photoshop are revolutionizing the way many artists, and perhaps most designers, work.

There is, and will always be, a role for such systems. Indeed, the vast majority of practicing "computer artists" will always use such "canned," preexisting software. It would be absurd to propose that all, or even many, artists pay the substantial dues required to get up to speed in this peculiar process I am describing. No, this process will always exist and be practiced on the fringes--there will never be more than a handful of people who are qualified to use this process, requiring as it does an extensive background in art, science, mathematics, logic, and computers.

Let me use an analogy: there have been great drivers, for almost as long as there have been cars. But these drivers are rarely the builders of the cars they drive. Indeed, no single person can expect to build an automobile of any sort, much less a race car, without the help of many others (no more can I expect to build the computers I use, or to have invented every technique I apply). But a good driver, whose vehicle is largely the result of their own creative vision, would always be a special competitor, though they might never turn in the fastest time.

There will always be room for the virtuoso users of tools provided by others, and such users can always be expected to predominate the field of performers. The greatest violin maker is not the greatest violinist. Likewise, there will always arise, here and there, now and again, visionaries with "the madness of the poet" who will create their own tools and do with them what might never have occurred to others. And there is, at least, always some significance to being the first to have done something of interest and of significant difficulty. This process I describe is probably best characterized as such an undertaking.

5. 3.  The Role of Traditional Media

New as it may be, this process certainly does not stand outside precedence. As the result is a two-dimensional work, all the rules and discipline of two-dimensional art apply, most saliently those of visual composition and color usage. As the modeling is done in three dimensions, rules of form and lighting also apply. When animation is undertaken, the rules of cinematography will come into play. When we produce a tangible product, any sort of physical manifestation, all the rules and practice of the medium in which that product is executed will apply. We cannot presume to create a new art form in a vacuum; we will need to borrow and appropriate everything we can use, from what has come before.

We may, however, need to invent a viable new medium in which to represent the product. It may be that computer art as a whole will not truly come into its own, until some essentially new display technology, such as large, bright, flat panel color displays or laser projectors, comes into common usage. Immersive VR technology, for instance, holds considerable promise as the unique, new medium for the apotheosis of computer imagery.

5. 4.  Mastering the Process and Medium

As painting has been mastered, so must this new process. Painting, photography and sculpture did not reach maturity overnight; neither can we expect computer art to do so. The fact is, the computer artwork has not yet been produced which could stand a side by side comparison with, say, a great van Gogh painting. My own best image would pale, stood beside a Bierstadt. The austere beauty of the underlying formalism denies computer generated imagery access to the fascinating, continuous behavior of such a medium as oil paint--there is simply nowhere near the amount of information in a standard digital image file, as there is in a well executed painting. The range of scales over which a good painting is interesting is also generally much larger than that for a computer generated image, fractals notwithstanding. There are at least two scales at which a good painting is interesting: the large scale, where visual composition predominates, and the small scale, where surface texture, impasto, juxtaposition of colors (as with Seraut) in a stroke, etc. , provide another visual richness. We will need to include such complexity, or simply find another grounds for legitimacy with as great an aesthetic significance, before we can call our works truly fine art.

One interesting and useful distinction was drawn by Ansel Adams, who posited the analogy of the negative as the score, and the print as the performance. In this analogy, we currently have the capability in this new process to produce the negative or the score, almost literally. But we currently lack the means of translating this score into an impressive performance. That is the challenge of creating the final artwork.

One wonderful distinction of the process I've presented is its simultaneous use of both analytic and intuitive thinking. Sitting at the computer creating an image, one must rapidly switch back and forth between the "right brain" mental faculties required to assess aesthetic issues and the "left brain" analytic processes required to deal with the logic-based machinery of production. This is certainly an unusual way to go about producing a visual artwork; its closest analogue may be in musical composition.

6.  Conclusions

This new process may mark a truly novel event in the history of creative process in the fine arts. Provided, of course, that the artist intends, understands, and can in some valid sense take responsibility for, the formalisms behind the product. I am claiming that a number, along with the appropriate (and well defined) interpretation machinery can represent artistic self-expression, that this number can be derived deterministically, and that the method of this derivation adds conceptual significance to the result.

Be careful to note that I am not claiming that the machine is self-expressing. A computer has no more aesthetic ability than any inanimate object, and indeed, it can be more refractory than most. The expression is the human artist's; the computer is the tool through which the artist makes his or her statement, it is at best an idiot savant assistant.

Biographically, I wish to add that it is fortunate that landscapes are my personal predilection for self-expression. In painting and photography, I have always preferred landscapes. When I entered the field of computer graphics research, landscape modeling and rendering were in their infancy; it has been my pleasure to substantially improve the state of the art in such through the course of my doctoral research [8] at Yale University under Benoit Mandelbrot, the father of fractal geometry. In a remarkable bit of serendipity, I appear to have been the right person in the right place at the right time. There was a narrow temporal opportunity, that I happened to precisely meet; had I shown up a few months or years earlier or later, the opportunity would not have existed.

6. 1.  Constraints and Opportunities

Let me quickly recap the significant constraints and opportunities of this new process, as I see them.

6. 1. 1  Working in Three Dimensions

While sculptors and stage designers have worked in three dimensions for millennia, the peculiar way in which we do so in this new process is significantly different. We differ at least in scale: we are creating landscapes, entire planets, and even, potentially, a finite synthetic universe. The challenges are different, and appropriate practice will therefore undoubtedly be different. Thus we will need to invent and refine some new methodologies. While landscape rendering has as rich a precedence as any other area of visual art, prior landscape artists were not generally responsible for creating their entire scene, in full three dimensions. Soon, when interactive exploration of our scenes becomes possible, we may also find ourselves confronted with responsibility for guiding, through whatever means we find artful, the explorations of visitors to our worlds.

6. 1. 2  Algebraic Color

While we cannot and should not expect to redefine the rules of color usage, neither can we manipulate color in the ways which visual artists are accustomed. First, we work in the unfamiliar additive color space, where heuristics for mixing colored pigments are either inverted or simply invalidated. Second, there is no physical system in which color interacts--it is all simply a model. Nothing happens at all, except for what we explicitly specify. We may seek to have those specifications mimic as closely as possible the behavior of the real world (a very hard thing to do, in general) or we may bend or break such laws in our system. In any case, the specification and interactions of colors on surfaces is couched in the mathematical language of algebra--certainly an unfamiliar way of dealing with color for the average studio artist. Colors are all numbers; they mix by the arithmetic operations of addition, subtraction, and multiplication, and they are often modulated by exponential operators (such as gamma correction).

Color theory for computer graphics is often elegant, and is quite internally consistent. But it is not something familiar to the average artist.

6. 1. 3  Proceduralism

Proceduralism, the practice of encoding behaviors in formally defined, deterministic functions, is at the very heart of this process. Strict adherence to this practice is whence the intellectual significance we claim for the process emanates. We can gain a wonderful elegance in this approach, as with the fractal models that can so succinctly describe manifestations of potentially unbounded visual complexity. It is a significant challenge to maintain the discipline of using only such relatively simple logical constructs for visual expression, and it is a significant constraint to work only with global parametric control.

There can come great benefits from such discipline, though. Imagine a procedurally defined planet, or array of planets, which possesses a wealth of detail everywhere, detail that the artist did not explicitly and laborious specify, but which issues directly and automatically from the functions from which the model is composed. Plates 2 and 3 illustrate an example of such a model: Plate 2 shows an entire planet and Plate 3 is a landscape that is actually physically situated on the face of that planet!  The animation "Spirit of Gaea," currently in production, will serve as a proof of this concept. In this animation, the point of view will move in from deep space, up to the planet, down through its atmosphere to its landscape, up very close to the terrain (the equivalent of a few feet away), then straight back out into deep space. This will all be accomplished with a single procedural model, and while rendering will be far from real-time, it is only a matter of engineering to get to where we can move around the planet (and its universe) interactively, at will. That will be an unprecedented development.

6. 1. 4  Ambiguities in Logic and Art

Our use of formal logic for self-expression entrains with it the precision and lack of ambiguity of mathematics and science. Lack of ambiguity is not familiar, or even desirable, in the arts. But such precision in the creative process does not in any way preclude the kind of deliberate ambiguity that lends depth and interest to art. Rather, it stands beneath, as an unusually solid foundation for artistic creation. Its use allows scientific models to mapped into creative opportunities--something that I personally find an exciting undertaking, having always been fascinated with the beauty of such models in their own right. Finally, our basis in formal logic entrains with it the intellectual depth of the philosophical discipline of logic and the mathematical models of the sciences. These are deep conceptual roots indeed, which we have only begun to tap.

6. 2.  Some parting Questions

I will conclude with some questions, questions that do admit to immediate answer.
 
  • How do we obtain self-expression through formal logic?

  •  

     

    I claim to have done so, but I can no more tell you how than the average painter can tell you precisely how they painted a particular painting. I hope that, with my own artworks, I have shown it to be possible, and I fervently hope to be surpassed by future practitioners.
     

  • How do we know when we have?

  • If my claim is valid, it should be verifiable. There are only two ways to do this: Ask the artist, and ask yourselves, the audience. Success or failure will be found to be a fickle thing.
     

  • So what's new here?

  • I have attempted to illuminate that in this essay, nevertheless I feel very incomplete about it. My own analysis of this event is preliminary; I may spend the rest of my days fleshing it out. It seems to me that, as is typical in new areas of intellectual inquiry, the ideas formulated and presented to date are perforce preliminary and vague. Certainly my own arguments could benefit from a deeper foundation in the history of art. But I hope that the time is ripe to begin to expound them, that they might be honed or discredited through the dialectic.
     

  • Is it important?

  • Time, of course, will tell, at least in the eyes of our culture. Obviously, I think so. But then, I am primarily trained as a scientist rather than as an artist, and I am certainly not an authority on art history. Nevertheless, I do know enough to recognize and put my professional reputation at stake, that something big is going on here. Unfortunately, the requirements for a full appreciation are backgrounds in mathematical logic, natural sciences, and computer science, as well as aesthetic training and sensitivity. Thus the audience who can apprehend, and perhaps be impressed by, these arguments is necessarily small.
     

  • Will it fly?

  • Again, time will tell. If I continue to suffer occasional visual inspiration, I may help bring it to maturity as an art form. I am certainly counting on others to help, and hopefully to soon create works that will make my own appear crude and preliminary. Fortunately I am not alone in my views or my efforts. To quote Judson Rosebush [12]:
     
    In practice, proceduralist computer art is among the most contemporary products of our culture, and will increasingly be appreciated as a major art movement by this and future generations. 

    If Mr. Rosebush and I are correct, we may be witnessing one of the truly definitive events in the history of Art.


    Bibliography


    [1]  Dawkins, R. , The Blind Watchmaker, 1987, New York, W. W. Norton & Co.\
     
    [2]  Ebert, D. S. , ed. , Textures and Modeling: A Procedural Approach, 1994, Academic Press, Cambridge, MA.
     
    [3]  Hart, J. C. and T. A. DeFanti, Efficient Antialiased Rendering of 3-D Linear Fractals, Computer Graphics, July 1991, 25:4, pp. 91-100.
     
    [4] Hofstadter, D. R. , Gsdel, Escher, Bach: an Eternal Golden Braid, 1979, New York, Vintage Books.

    [5]  Kuhn, T. S. , The Structure of Scientific Revolutions, 1970, Chicago, University of Chicago Press.

    [6]  Land, E. H. , Six Eyes of Man, Three-Dimensional Imaging, SPIE, 1977, 120, pp. 43-50.

    [7]  Mandelbrot, B. B. , The Fractal Geometry of Nature, 1982, New York, W. H. Freeman and Co.

    [8]  Musgrave, F. K. , Methods for Realistic Landscape Imaging, 1994, Ann Arbor, Michigan, UMI Dissertation Services (Order Number 9415872).

    [9]  Musgrave, F. K. , A Panoramic Virtual Screen for Ray Tracing, in Graphics Gems III, D. B. Kirk, Editor, 1992, Academic Press, Boston.

    [10]  Neitz, M. and J. Neitz, Numbers and Ratios of Visual Pigment Genes for Normal Red-Green Color Vision, Science, 1995, 267:February 17, pp. 1013-1016.

    [11]   Nielson, G. M. , Visualization in Scientific and Engineering Computation, IEEE Computer, September 1991, 24:9, pp. 58-66.

    [12]  Rosebush, J. , The Proceduralist Manifesto, Leonardo, 1989, :supplemental issue, pp. 55-56.

    [13]  Russell, B. and A. N. Whitehead, Principia Mathematica, 1962, Cambridge University Press.

    [14]  Sims, K. , Artificial Evolution for Computer Graphics, Computer Graphics, July 1991, 25:4, pp. 319-328.

    [15]  Smith, A. R. , Plants, Fractals, and Formal Languages, Computer Graphics, July, 1984, 18:3, pp. 1-10.

    [16]  Todd, S. and W. Latham, Evolutionary Art and Computers, 1992, London, Academic Press.

    [17]  Verostko, R. , Epigenetic Painting: Software as Genotype, Leonardo, 1990, 23:1, pp. 17-23.

    [18]   Waddington, C. H. , The Strategy of Genes, 1957, London, George Allen and Unwin.

    [19]  Wyszecki, G. and W. S. Stiles, Color Science: Concepts and Methods, Quantitative Methods and Formulas, 1967, New York, Wiley-Interscience.
     
     


    Footnotes

    [1] The term "string" has a very specific definition in computer science, but for our purposes it is sufficient to think of it as an arbitrary sequence of characters or digits.
     

    [2] See Douglas Hofstadter's "Gsdel, Escher, Bach" [4] for a thorough layperson's treatment of formal systems. Bertrand Russell and Alfred North Whitehead's "Principia Mathematica" [13] provides the definitive mathematical treatment thereof.
     
    [3] Note that throughout the text, I will freely use the term "random," generally meaning "pseudo-random" and thereby implying an ultimate determinism.
     
    [4] One could technically contest the claim that this is a one-pass process, on the grounds that the terrain models I image have generally been generated outside of the rendering process, in a separate step. In my own defense I point out that A) I apply the same rules of algorithmic purity in the terrain-model generation process, B) the program that generates the terrain could readily be incorporated into the renderer thus coupling them, and C) I am moving towards exactly that: a completely procedural process wherein even the terrain model is created on-the-fly as the picture is being created. (See Plates 2 and 3, which are entirely procedural. )
     
    [5] The subjectivity of the aesthetic gradient function is brilliantly illustrated in Karl Sims' installation of interactive genetic art at the Pompidou Museum in Paris, and in certain interactive web sites, where the viewer is allowed to "vote" on an image they favor, which is then developed further. While driven by a deterministic program, the process is highly divergent--different viewers will generally express different preferences, as dictated by their internal aesthetic gradient function which indicates to them "which direction to go in" to obtain a "better" image. My own experience with Sims' system indicates that it might well comprise a semi-deterministic testbed for assessing a user's aesthetic discrimination: A user with superior aesthetic discrimination will converge more rapidly on interesting images.
     
    [6] Because the projection is described in the abstract, with mathematics, we may employ projections which would be difficult to impossible to obtain with a camera, such as one which instantaneously maps the entire celestial sphere to the image plane. [9]  Indeed the abstract projections may be quite non-intuitive as, for example, in the projection of a four-dimensional quaternion Julia set down into three dimensions, and subsequently down to the two dimensions of the image plane. [3]
    [7] I often perform my computations in parallel on several computers, each of which is capable of performing several million operations per second.
    [8] Further analysis of the character of this seductive appeal leads down a more epistemological path than we choose to pursue in this essay; we refer the interested reader to Kuhn. [5]
     
    [9] An essential element of the full philosophical definition of formal systems is that they are closed systems: They make absolutely no reference to anything outside of themselves. Thus they are perfectly divorced from any intrinsic meaning--as implied, for instance, by correspondence to the behavior of real-world phenomena. While this has bizarre consequences for the foundations of scientific reasoning, for us, in this artistic inquiry, it simply points to the fact that all "meaning," no matter how intentional or self-evident in our results, is simply an act of creative ascription and not an inherent property of the system.
     
    [10] The tristimulus model of color vision is predicated on the long-standing observation that there appear to be three distinct types of color receptors in the human retina, which are sensitive to red, green, and blue light. Recent genetic research indicates that there may actually exist the potential for several long-wavelength (red) photoreceptors. [10]  This might have interesting consequences for our best models of the range and limits of human visual perception.
     
    [11] A fascinating observation is that many of these possibly bit-strings will actually be illegal to possess or circulate as some will, by exhaustion of all possible images, represent scenes such as child pornography!  Of course, the chances of deriving such a string are minuscule and furthermore, as Gsdel's Incompleteness Theorem shows, not all strings are necessarily derivable within any given formal system or program. As Terence McKenna points out, it will be more fascinating still when we develop formal systems so potent in their range of visual (or other) expression that the formal system itself will be perceived as a sufficient threat to the dominant paradigm that it will be declared illegal.