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.
One key difference between cellular automata and the universe is that the former are discontinuous in both space and time.
Alluding to the law of non-decreasing entropy, Wheeler used to jest that if he placed a hot cup of tea next to an iced cup and allowed them to even out their temperatures, he’d commit a crime by raising the amount of entropy in the universe.
Wheeler’s dropping of cups into the universe would enlarge the black hole’s invisible frontier and thereby lead to a net gain in entropy after all.
If the universe itself is a digital system involving superpositions of zeroes and ones, who would take the measurement that triggered “Collapse” into definitive values? Wheeler knew that it couldn’t be someone outside of the universe, so it would have to be activated from within by internal observers.
Wheeler pondered the concept of a “Self-excited” circuit, in which astronomical measurements of the past force the digital information in the early universe to assume particular values.
Today, as laboratories around the world are striving to perfect quantum computers, it will be interesting to see how the notion of the universe as a cellular automaton develops.