Decoding Reality

A well-recommended book, but it doesn’t explain its key assumptions, and so I feel that it’s conclusions should be limited to ‘the understood aspects of reality’ rather than the whole of reality.


Decoding Reality: the universe as quantum information, Vlatko Vedral, 2010, has been recommended to me by quite a few Physicists with an interest in quantum mechanics and information.

The theme is ‘information is Physical’, but I am never clear if:

  1. our perception of the world is constructed from our information
  2. things are the way that they really are because of information.

The language seems to wander from one to the other. Also, (p 28) Vedral follows Aristotle in linking information to probability, and (p 31) credits Shannon with this. Yet Shannon only deals with the ‘technical’ problem, making assumptions that – as Keynes noted – appear not to be universally valid. Weaver’s introduction to Shannon covers this.

A key metaphor is of sculpting (p 205). As science is developed what remains to be explained reduces towards nothing, although a new viewpoint can focus on previously unappreciated possibilities. This is quite different from a view in which attempts to apply science create new complexities to be understood. While it may be true that this ‘completely and faithfully embodies the spirit of how science operates’, there is no discussion of the alternatives, and which may be more effective. Much of my difficulties with the book seem to flow from this assumption. For example,

  • While it is recognized (p 193) that ‘all quantum information is ultimately context dependent’, the discussions on probability and information neglect the role of context (e.g. p 189).
  • The approach is explicitly pragmatic, in the sense of using a model until it clearly fails. Is this wise?
  • The book uses the word ‘reality’ for our conception of it. Thus in 2006 the financial boom was ‘really’ going to continue forever: we had no way to talk about the crash until it happened. Thus this type of ‘science’ cannot handle uncertainty without introducing paradoxes.
  • Specifically (p 170) there is only randomness and determinancy, yet the notion of randomness is narrower than uncertainty.
  • No mention is made of Turing, whom one might have thought central.
  • It interprets Occam’s razor as favouring the theory with the shortest description (p 166), rather then the one with the fewest assumptions.


Much of what is said is valid within an epoch, but unhelpful more generally. Perhaps one could compromise on “the understood part of the universe as the understood part of quantum information”. Alternatively, given Vedral’s usage of ‘real’ perhaps the title could stand. But then the ‘unreal possible’ might surprise us.

See Also

Allen , induction , pragmatism , metaphors – see quantum .

David Marsay


About Dave Marsay
Mathematician with an interest in 'good' reasoning.

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