Randomness is a slippery term that conveys different meanings in different disciplines. In mathematics, an individual number is random when there is an equal chance for it to be any number from a set of possible values. In computer science the term becomes more relative and numbers have varying degrees of pseudo-randomness. Information theory equates randomness with unpredictability and, at odds with other definitions, concludes that a higher level of randomness indicates a greater concentration of information; a message’s probable denseness of information is highest when the message is partially surprising and partially expected.There is no fixed definition for what randomness means in art, but analogies can be drawn to how the term is used in other fields. For example, information theory’s definition might suggest that artworks have the greatest impact when using a mixture of pattern and unpredictability.
Random is often used colloquially to indicate arbitrariness or things unrelated: random acts of violence, random thoughts, random encounters. A number of fields such as computer science, statistics, and informational theory have more rigorous definitions of randomness. But each of these fields uses the term in a way that is slightly at odds with the others.
As a starting point, let’s establish what randomness means to a mathematician and, using that, build a working definition for what randomness might mean to an artist. In mathematics, an individual number is random when there is an equal chance for it to be any number from a set of possible values. When describing a sequence of numbers as random, we mean each number is statistically independent of the others; that the numbers in the series have no effect or relation to the others (Haahr, 2008). A random number or sequence is characterized as containing no meaningful information; if a number conveys some data (such as the result of a formula, a person’s phone number, or the number of times the letter ‘q’ appears in this chapter2), then it is not random.
This trait of non-significance can be borrowed and used as a key characteristic of randomness in art. If an element in an artwork contains some meaningful information about the world around us, then the element isn’t truly random. Consider this recipe by Tristan Tzara (one of Dada’s founders) for writing poetry:
To Make A Dadist Poem
Take a newspaper.
Take some scissors.
Choose from this paper an article the length you want to make your poem.
Cut out the article.
Next carefully cut out each of the words that make up this article and put them all in a bag.
Next take out each cutting one after the other.
Copy conscientiously in the order in which they left the bag.
The poem will resemble you.
And there you are--an infinitely original author of charming sensibility, even though unappreciated by the vulgar herd. (Brotchie, 1991, p. 36)
Key Terms in this Chapter
Pseudorandom Random Number: A number that was generated using an algorithmic process called a pseudorandom number generator (PRNG). Because the numbers are created deterministically they have the appearance of randomness, but are not truly random.
Hardware Random Number Generator: A method for generating random numbers using a physical process, such as the nuclear decay of radioactive material. The generated numbers are often referred to as “true random” numbers in contrast with pseudorandom numbers generated by a pseudorandom number generator.
Chaotic: behaviors where minor changes in initial conditions can result in widely divergent results. Chaotic systems often appear random even though they are completely deterministic.
Chance: In this chapter “chance” refers to unpredictable, but deterministic, events.
Generative Art: Art that is created according to an algorithm. Generative art is typically intended to give the appearance of machine creativity.
Deterministic: A situation where events are completely predictable based upon cause and effect.
Algorithm: A set of well-defined instructions for completing a task.
Random: used in this chapter to specifically refer to unpredictable events that are completely self-contained and communicate no information (in contrast to “chance”).
Quantum: Used in this chapter to refer to subatomic processes.
Stochastic: having unpredictable characteristics. Used in this chapter to refer to both random and chance events.