Review : David Deutsch – The Fabric Of Reality

This is a science post…

I was going to write another post about Final Crisis, but then I realised that I would have to explain a lot of what I was talking about, so this is a “I’m saying this so I can say this” post. It’s a bit of a tangent really, but I hope that you’ll be able to see the connections to some of the Final Crisis posts. Tomorrow I’ll write more about FC, and then I’m going to leave the subject of comics for a bit to do some politics, Doctor Who and music posts…

The Fabric Of Reality is an attempt by Deutsch, a physicist who specialises in quantum cosmology and quantum computing, to explain for the layman the worldview he has come up with, sort of a unified theory of reality (not to be confused with the unified field theory which physicists have been searching for for decades). This worldview is based on four strands:

The multiversal interpretation of quantum theory
This view states that every time anything could happen, it does – there are a near-infinite number of universes which differ by the smallest possible measurable amount. In Deutsch’s formulation of the multiversal interpretation, these universes aren’t ‘created’ by the ‘choices’ at the quantum level, rather every instant of time is in effect one point in a giant multi-dimensional array, and what we perceive as time passing is merely one path through this array.

Popperian epistemology
The philosopher Karl Popper stated that scientific knowledge grows by a process in which hypotheses are created and tested to destruction, with the hypotheses either being disproved or surviving, in a clear parallel to Darwinian natural selection. This can be contrasted with Kuhn’s ideas of ‘paradigm shift’. (And see this, which Holly serendipitously sent me while I was writing this…)

Dawkins’ modifications of evolutionary theory
Richard Dawkins, in his bestseller The Selfish Gene, posited that evolution acts, not at the level of the organism or species, but rather at the level of the individual gene.

and the Church/Turing hypothesis
This states in effect that any operation that can be performed by any computer can be performed by any other computer, given enough time and storage capacity.

Deutsch states that all these are the ‘current best thinking’ in their relative domains. Here he is quite probably wrong. The many-worlds interpretation is a minority view among quantum physicists , although its predictive power is the same as any other interpretation and Deutsch makes a good case that it is the clearest explanation. Popper’s epistemology, while I think he’s right, is nowhere near as popular as Kuhn’s. Dawkins’ view, while popular with many biologists, is regarded with suspicion by others (see Jack Cohen’s writing for example, as well as obviously Stephen Jay Gould) though if one were to reword his ideas taking gene to mean ‘all means of transmissible information storage within the organism’ then it would work better. And the Church/Turing hypothesis has never been proven (it’s a mathematical statement so concepts of proof apply in a way they don’t for science) though it’s strong enough to be the basis of pretty much everything we do in computing today.

However, one *can* say that none of the explicit bases for Deutsch’s argument are provably wrong, and from them he builds a consistent view of reality. This view requires a lot of implicit extra assumptions, though, including that the universe is fundamentally understandable, that consciousness is a purely physical process, that the human brain is a computer of sorts, and so on. Most of these are justifiable using Occam’s razor (which Deutsch uses a *lot* and which I must post about soon – I was having an argument with Mat and Jennie about this the other day and they quite rightly said that William of Ockham used the original formulation to essentially say that God explains everything. However, it can be shown that a reformulation of Occam’s razor is necessary and sufficient as a basis for the scientific method when combined with some mathematical proofs…) but with each of them the probability of his worldview being the correct one becomes less – if any one of these is wrong, his whole argument falls down.

It’s also interesting which strands of scientific theory he’s chosen as ‘fundamental’ (in Deutsch’s view, which I think is correct, ‘fundamental’ should mean ‘has the most explanatory power’. All else being equal the best story wins. This will be important when I get back to comics eventually…). Were I to attempt something similar to Deutsch’s book (and I’ve been tempted to – only my lack of formal qualification has stopped me, for which the world should probably be eternally grateful) I would have chosen, say, quantum theory (without any particular interpretation being put on it), the second law of thermodynamics, Ashby’s Law of Requisite Variety (Gavin R, if you’ve never read Ashby, you should – he’s at least as important as Shannon) and Bayesian statistics. Oddly, I would have come up with a formulation that is not that dissimilar from what Deutsch comes up with…

Deutsch’s book is by turns fascinating and infuriating – he shares a lot of qualities with his Oxford colleagues Dawkins and Roger Penrose (with whom he fundamentally disagrees, but in an admiring way), making me at several points want to throw the book across the room screaming “You stupid, STUPID man!” (especially in the last chapter – I want a moratorium on anyone talking about ‘the singularity’ unless and until it actually happens, please) but occasionally coming up with something that makes me sit up and say “That’s actually very interesting…” (something Dawkins has never achieved). I also found his introduction (about the childhood horror at not knowing *everything*) very easy to relate to.

But his main insight is simply this – Information can, in this worldview, be described as “That which remains constant more often than not between universes”. I’ll explain why this is tomorrow, before talking about DC Comics and Grant Morrison some more…