Nature contributor David Chandler writes about the late Prof. Edward Fredkin and his impact on computer science and physics.
“Fredkin took things even further, concluding that the whole Universe could actually be seen as a kind of computer,” explains Chandler.
“In his view, it was a ‘cellular automaton’: a collection of computational bits, or cells, that can flip states according to a defined set of rules determined by the states of the cells around them. Over time, these simple rules can give rise to all the complexities of the cosmos — even life.”
According to the followers of this concept, traditional physical equations can be replaced by more understandable rules for the functioning of computers, especially when it comes to quantum computers.
The essence of this idea is that the laws of physics and the structure of the universe can be the initial result of a complex computer algorithm.
However, such a revolutionary concept requires further research and verification. In order to prove that space and time consist of discrete data, it is necessary to conduct detailed experiments at the level of the Planck scale. This is the scale at which existing physical theories can fail.
“The basic idea of a digital Universe might just be testable. For the cosmos to have been produced by a system of data bits at the tiny Planck scale — a scale at which present theories of physics are expected to break down — space and time must be made up of discrete, quantized entities”, says Seth Lloyd, a mechanical engineer at MIT who in 1993 developed what is considered the first realizable concept for a quantum computer2.
“The effect of such a granular space-time might show up in tiny differences, for example, in how long it takes light of various frequencies to propagate across billions of light years. Really pinning down the idea, however, would probably require a quantum theory of gravity that establishes the relationship between the effects of Einstein’s general theory of relativity at the macro scale and quantum effects on the micro scale.
“This has so far eluded theorists. Here, the digital universe might just help itself out. Favoured routes towards quantum theories of gravitation are gradually starting to look more computational in nature”, says Lloyd — for example the holographic principle introduced by ‘t Hooft, which holds that our world is a projection of a lower-dimensional reality.
“It seems hopeful that these quantum digital universe ideas might be able to shed some light on some of these mysteries.”
So far, this question remains open, but the digital structure of the Universe can have an important impact on its resolution.
Scientists are also looking to the holographic principle proposed by Gerard Hooft as a potential solution to this dilemma.
He suggests that our world may be a projection from a lower dimension, which in some way corresponds to the idea of a “digital universe”. This principle can provide new clues and guidelines in the development of the quantum theory of gravity.
Research in this area is just beginning. Perhaps we are on the cusp of a new era in our understanding of the universe, where computer algorithms can help unlock its secrets.
If the idea of a “digital universe” turns out to be true, it will be a turning point in the history of our understanding of the world around us, and perhaps we will reconsider not only the laws of physics, but the very foundations of reality.