In the early 1970s, computer programmers around the world were entranced by the strange happenings taking place on their screens. Right before their eyes, they observed digital creatures emerging from the void, crawling around, propagating, gobbling each other up, and vanishing into nothingness. It was all part of John Conway’s popular Game of Life: a simple algorithm that produced remarkably complex patterns.
The Game of Life starts with a checkerboard grid in which each square, or “cell,” is populated by a binary piece of digital information—a bit—set to either zero or one. For the purposes of the game, zero represents non-existent or “dead” (an empty cell) and one represents “alive” (an occupied cell). After the initial values are seeded, the screen is updated repeatedly—with each iteration depending on the previous one according to rules based upon each cell’s immediate neighborhood.
DAVID HUA, YONATAN BIEL, AND MARTIN PELIKAN / STARS-2012 PROGRAM
Whenever an empty cell (with a zero) is surrounded by precisely three occupied cells (with ones), a “birth” takes place upon the next iteration, and it becomes occupied. If a living cell has fewer than two other living cells in its vicinity it “dies” of “underpopulation.” More than three, and it “dies” of “overpopulation.” Only if a living cell has two or three others in its neighborhood does it survive until the next round. The result is an ever-evolving series of patterns, resembling living creatures. Some of these configurations, such as the so-called “glider gun” (developed by Bill Gosper and sometimes known as Gosper’s glider gun) seem to produce recurrent streams of “organisms,” spawned like tadpoles from digital “parents.”
Conway’s brilliant game constitutes a subclass of a more general mechanism called a “cellular automaton,” developed in the late 1940s and early 1950s by John von Neumann and Stanislaw Ulam as an outcrop of the computer revolution. The necessary ingredients for such a system include a network (one-dimensional, two-dimensional, or even more intricate), a set of values (usually binary), and a set of simple, deterministic rules for iterations that most often depend on the values in each neighborhood of cells. While the original cellular automata had irreversible rules, some are fully reversible—acting identically forward and backward in time. The reversible versions thus bear some similarity to Newtonian mechanics, albeit with discrete time-steps, rather than continuous behavior governed by differential equations.
Computers execute complex functions based on rudimentary operations involving bits. Could the universe itself, at its deepest level, operate on the basis of similarly discrete digital rules? Such a scenario was speculated in the 1960s by innovative thinker Ed Fredkin, and later dubbed “It from Bit,” by the accomplished physicist John Wheeler. It has remained the focus of much debate surrounding the significance of cellular automata.
More information:
https://arxiv.org/abs/physics/9907013
https://www.stephenwolfram.com/media/universe-black-white/cell.html
