David Deutch - The Fabric of Reality

In view of all the unifying ideas that I have discussed, such as quantum computation, evolutionary epistemology, and the multiverse conceptions of knowledge, free will and time, it seems clear to me that the present trend in our overall understanding of reality is just as I, as a child, hoped it would be. Our knowledge is becoming both broader and deeper, and, as I put it in Chapter 1, depth is winning. But I have claimed more than that in this book. I have been advocating a particular unified world-view based on the four strands: the quantum physics of the multiverse, Popperian epistemology, the Darwin-Dawkins theory of evolution and a strengthened version of Turing’s theory of universal computation. It seems to me that at the current state of our scientific knowledge, this is the ‘natural’ view to hold. It is the conservative view, the one that does not propose any startling change in our best fundamental explanations. Therefore it ought to be the prevailing view, the one against which proposed innovations are judged. That is the role I am advocating for it. I am not hoping to create a new orthodoxy; far from it. As I have said, I think it is time to move on. But we can move to better theories only if we take our best existing theories seriously, as explanations of the world.

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Michael Lockwood, ‘The Many Minds Interpretation of Quantum Mechanics’, British Journal for the Philosophy of Science, 1996, Vol. 47, No. 2.

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Actually mathematical theorems are not proved by ‘pure’ argument (independent of physics) either, as I shall explain in Chapter 10.

Actually it could still be true universally, if other theories about the experimental set-up were false.

Tipler replies:In my first paper on the Omega Point Theory (“Cosmological Limits on Computation”, International Journal of Theoretical Physics, 25, 617-661 (1986)), I also used the Turing Principle to derive the OPT. Subsequently, I’ve generally used the Eternal Life Postulate (Life goes on forever in the universe) to derive the OPT. But since life is collectively a Universal Computer (if it goes on forever), the Turing Principle and the Eternal Life Postulate are equivalent. As I outline elsewhere on this web page, one can also derive the Omega Point Theory directly from the most fundamental laws of physics. Thus the laws of physics imply both the Turing Principle and the Eternal Life Postulate.

Tipler replies:The Omega Point exists, but indeed He/She is not part of the physical universe of spacetime or matter. The Omega Point is the future c-boundary — the future singularity — which is not part of spacetime, but is instead the “limit” of spacetime (the mathematical term is “completion”). The irrational numbers such as square root of 2 or pi are equally the limits of rationals (the technical term is “Dedekind Cut”), but nevertheless the irrational numbers just as “real” as the rational numbers. As Deutsch points out earlier in his book, general relativity predicts the existence of singularities, so following the epistemological rules which Deutsch himself has laid down earlier in this very chapter, if a corroborated theory like general relativity says something exists, we have to accept it unless and until an experiment tells us otherwise. In rejecting the existence of singularities, Deutsch is being an inductivist. The Turing Principle tells us the Omega Point exists, and further, some events actually are occurring now in order to force the multiverse to evolve into the Omega Point. Anything that effectively acts on matter is real .