As I mentioned last week, The Fabric of Reality is a thought-provoking book, but sometimes it’s just provoking. The book spends too much time blasting away at theories that aren’t useful and misrepresenting theories that are commonly accepted, not enough time crossing over some of its logical leaps, and no time at all discussing valid alternatives. But it makes up for it at the end by a leap into science fiction.
The book begins by beats up so thoroughly on solipsism (the idea that I’m the only one who exists and you’re all illusions), instrumentalism (the idea that the whole worth of a theory lies in its predictions) and positivism ( the idea that we can know only what we directly observe), you get the impression that these are still dominant ways of thinking. It gets so exercised about induction that it spends half a chapter destroying it, and another whole chapter to “crypto-inductivism,” the feeling of wishing we hadn’t destroyed induction.
The book turns the Copenhagen interpretation into a straw man by claiming it says that it requires a conscious observer to collapse waveforms. It spends a lot of time and space beating up on spacetime, stating unequivocally, several times, that spacetime physics is wrong. We then get rid of it by slicing and dicing and shuffling spacetime into nonsense.
The book seem to think too many things are “self-evident,” often making bald statements and expecting you to agree. True, some of the connections are evident, such as the similarity between the advancement of scientific theory and natural selection. Some of the connections aren’t. Tell me again how exactly genetic replication is the same as a virtual reality generator?
I found the whole argument justifying virtual reality generators troublesome. The book extrapolates the Church-Turing thesis (which seems to be if you can design an algorithm you can compute it) via Penrose to the strong form of the “Turing principle”:
It is possible to build a virtual-reality generator whose repertoire includes that of every physically possible environment.
In other words, all physical reality is computable, which is why why we can understand the universe. I love this idea but I just don’t see how we got there. Given the shaky ground this principle stands on, it’s hard to accept it when the book uses it to justify other arguments.
The first major omission comes in the chapter about the two-slit experiment and the multiverse, when it completely ignores the common explanation that photons are like waves and like particles but are not actually either. When the book discusses the universal Turing machine, I was disappointed that it doesn’t address the idea that the universe is a quantum computer. And it’s particularly annoying for it to challenge the reader to prove Shor’s algorithm (which uses quantum computing to factor numbers) doesn’t compute across multiple universes, as if explanations that don’t need more than one universe didn’t exist. Not to mention that existing implementations haven’t actually computed much.
The Last Frontier:
The last chapter discussing the Tiplerian Omega Point is an unbelievable mix of the fantastic and the bizarre. Leaving aside the fact that a Big Crunch is currently out of favor, we receive a vision of all life in the universe converging and creating a stratum where they all exist in a virtual reality that they control, becoming omniscent, omnipresent, and omnipotent. Naturally we have no idea what these beings would want, but surely they would reach back in time and resurrect all their ancestors who suffered in life and give them a “heaven” to exist in until the end of time, which would appear to recede into infinity indefinitely, and thus confer the illusion of immortality. Really? You know, I enjoyed reading about the Riverworld, but I don’t want to spend eternity there.
I want to steal so many of these ideas, but there are too many gaps in the arguments for me to feel comfortable playing with them. But I know others have. For instance, I recognize some of this book’s ideas in Brasyl. I have the sneaking suspicion that some of the missing logic is in the sources in the “required reading list.” Fair enough. Most of them are books I’d like to read someday anyway.
My mind is throughly bent. Ow.