The Case Against Reality - Donald Hoffman ***

It's not exactly news that our perception of the world around us can be a misleading confection of the brain, rather than a precise picture of reality - everything from optical illusions to the apparent motion of video confirms this - but professor of cognitive science Donald Hoffman goes far beyond this. He wants us to believe that spacetime and the objects in it are not real: that they only exist when we perceive them. It's not that he believes everything to be totally illusory, but suggests that the whole framework of the physical world is a construction of our minds.

To ease us into this viewpoint, Hoffman gives the example of the Necker cube - the clever two-dimensional drawing apparently of a cube which can be seen in two totally different orientations. Calling these orientations 'Cube A and Cube B' he remarks that our changing perceptions suggest that 'neither Cube A nor Cube B is there when no one looks, and there is no objective cube that exists unobserved, no publicly available cube waiting for all to see.' Yet surely this is disingenuous - there never was any cube, it's a two-dimensional drawing. There is no physical object.

Hoffman provides us with a good and interesting simile in the idea that our perception of the world stands in relation to reality rather in the same way that a graphical user interface does to the underlying bits and bytes in a computer (even if we do then suffer repeated Matrix references, which feel a bit dated these days), and we get plenty of good material on the limitations of the senses - but the extreme conclusions, dragging in evolution and the idea that objects don't exist if we don't observe them feels like an attempt to give a notion a lot more depth than it really has.

It seems pointedly misguided to posit that nothing exists when we don't construct it, then to give examples from 'nature' as if such a thing has an independent existence in this worldview. This contradiction comes through particularly strongly when Hoffman refers to black holes, something we have never directly observed and so, according to his argument, can't exist. Throughout there seems to be a a lack of distinction between models and reality.

From the physics viewpoint, there is a big red flag suggested by having the lead puff on the back of the book written by Deepak Chopra. In fact there is a distinctly Chopra-like attempt to align a theory with quantum physics without any scientific basis: the quantum physics that Hoffman describes seems to assume that quantum particles are constantly in states which are actually fragile and unusual as a result of particles interacting with their environment, causing decoherence. Quantum theory is no help in supporting these ideas of a world created by the observer. Perhaps the clearest example of a lack of understanding of physics is in the statement 'The interface theory predicts that physical causality is a fiction. This is not contradicted by physics.' Unfortunately, it is. Relativity certainly does away with the concept of simultaneity, but this does not mean that causality goes out of the window.

This remains an interesting, if frustrating, book, but it does feel very much like an attempt to construct a castle in the air. The emperor may have some clothes, but they're very skimpy.

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Review by Brian Clegg