- David Deutsch is an Oxford theoretical physicist. He is best known as one of the pioneers of 'quantum computing', which seeks to exploit the peculiarities of 'quantum interference' to perform – in principle, and perhaps in practice – computations which could not be performed by classical means. However, Deutsch's interests extend well beyond his home field.
- In The Fabric of Reality he defends radical conclusions about matters seemingly far removed from his home discipline. Given the ambitious, trans-disciplinary nature of Deutsch's project, and the fact that his book is aimed at the popular science market, the obvious comparison is with his Oxford colleague, Roger Penrose. Deutsch aims even higher than Penrose, however. Where Penrose argues for a novel connection between three of the hard problems of contemporary science (quantum mechanics1, gravity, and consciousness), Deutsch goes one better, and offers us a fourfold synthesis: quantum mechanics2, computation, evolution3, and Popperian epistemology.
- Thus Deutsch has set himself a very ambitious target. Too ambitious, in my view, for the effects of magnification are just what one might expect: details get lost, cracks get larger, and key points go out of focus. And where there is room for doubt, Deutsch has an annoying tendency to err on the side of confidence. So for philosophical readers familiar with Penrose's clear and carefully argued books, The Fabric of Reality is likely to be a disappointment.
- One example4: Deutsch maintains that quantum interference effects can only be explained by the many worlds view …
- In sum, Deutsch gives his readers a good sense of why he and many other physicists find the physical evidence for the many worlds view to be compel ling. But he fails to show that the evidence should still seem compelling, in the light of a more careful examination of the underlying argument.
- That task requires a nose for fine distinctions and a respect for logical rigour and clarity, and these are not the talents on display in The Fabric of Reality.
- Maybe Huw Price intended to add other examples, but his 4-page review restricts itself to this one.
- An important issue – though not Price’s main critique of Deutsch – is that Price points out that there’s a distinction between David Lewis’s logically possible worlds and the multiverse, which is a single possible world in the Lewisian sense. I’ve noted this myself on numerous occasions.
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