If this guy's theory were true, it would be an example of "Intelligent Design." Here, we find "The Cornell University Library" has published an article on the idea that the Physical Universve may simply be a 3-D Virtual Reality simulation, or in other words, an Intelligently Designed Universe.
From New Scientist:
The VR hypothesis
The idea that the universe is a giant virtual reality simulation is a well explored theme in science fiction. Films such as The Matrix have used this premise to great effect.
Now a New Zealand scientist is saying that physicists should seriously explore the idea. Brian Whitworth at Massey University says that it is perfectly reasonable to conjecture that "the world is an information simulation running on a three-dimensional space-time screen". Deciding whether or not this is true is a matter for science to resolve.
Assuming Whitworth is serious, what should we make of this idea? He readily admits that this is a weird idea but points out that it is no more strange than many widely held views in physics such as the many worlds interpretation of quantum mechanics, the big bang and Boltzmann brains.
So how would we be able to tell if our universe was a simulation? Whitworth says that if reality was to do something that information processing cannot, then it cannot be virtual. But he falls short of suggesting what this might be.
(As an aside, there are plenty of mathematical algorithms that are incomputable. They are the products of a physical human mind, so if they count as something that information processing could not come up with, Whitworth's idea is already dead in the water.)
Whitworth goes on to suggest various ways in which phenomenon associated with quantum mechanics and relativity can be explained in terms of VR.
He also claims that VR can resolve many of the philosophical questions associated with the Big Bang, such as what caused it and how could it arise when there was no space and time. His answer is that the universe simply booted up although he conveniently ignores all the questions that such a "Big Boot" would raise.
Whether the VR hypothesis is actually testable is a question Whitworth avoids. But without testable predictions about the universe that would distinguish this idea from other theories, the VR hypothesis is pure philosophy.
That's why it is almost certain to be ignored by mainstream physicists. It's not the first idea to suffer this fate - the physicist David Bohm proposed a small modification to quantum mechanics that made no difference to its predictions but ensured that the theory was deterministic.
Most physicists rejected it on the basis of Occam's Razor: that science should strive for the simplest theory that fits all the facts.
My guess is that Whitworth's work will go the same way.