Max Tegmark's Our Mathematical Universe - a quest for nature of reality

There are two ways in which a book can affect you. Either you read it, or you read reviews of it. I suspect many of us encounter more books through the second route than the first. This can be a problem if the reviewer's prejudices unduly bias the presentation of the material.

A recent case in point is Thomas Piketty's tome, Capital in the Twenty-First Century, on the evils of inequality and capitalism. Much early reaction was ecstatic with delight. Left-of- centre liberals seized on "scientific" proof that capitalism was ruinous for society if left unchecked. Later, less publicised commentators remarked on the limitations of Piketty's analysis. Whether or not you agree with Piketty, the nature of these reactions and the heat with which they were expressed is revealing. Highly emotional responses often result from how the ideas mesh with deeply held personal views, in this case in relation to what sort of society we should live in.

Now what has this to do with Max Tegmark's Our Mathematical Universe? Well, have a look at an online "review" by Peter Woit (another physicist), dismissively entitled "Not even wrong". The tone reveals much about how far Woit feels challenged at some fundamental level. My schoolboy mathematics is not up to assessing Tegmark versus Woit but his aggressive and highly personal tone is striking. Woit asserts that Tegmark's propositions are "empty" or "nonsensical" and concludes by wondering "why the scientific community tolerates … all this?" Shades of medieval book burning!

Why the hysteria? Tegmark's book falls into two parts. It begins by uncontroversially reviewing the history of human understanding of the cosmos. Then Tegmark develops his proposition; that the universe is inherently mathematical.

"Our reality isn't just described by mathematics, it IS mathematics," he says. "You and I are self-aware parts of a giant mathematical object."

Tegmark is addressing what reality "really" is, in a way that makes many feel uncomfortable because it undermines their most basic professional assumptions. This leads to efforts to reject the distasteful ideas with personal attacks. Historically, almost every major step forward in scientific understanding has proceeded in this way: hysterical rejection and marginalisation or worse. Giordano Bruno was burned at the stake for claiming the universe was infinitely large.

If you simply read Woit's review, you would conclude that Tegmark sets out a series of untested - and indeed untestable - speculations. In practice, he argues directly from basic assumptions which most people - other than Berkeleyan solipsists - accept; that there is an external reality, which exists even when you and I are not looking at it. From this seed and the emerging evidence of the structure of the cosmic background radiation from the time of the big bang, Tegmark develops the idea of not just one but a tier of multiverses as the inevitable consequence, one of which we inhabit but as a vanishingly small element of the vast whole. So far this is controversial but not new. By framing his proposition about reality as a mathematical structure, however, he presents it in a different way. Everything is mathematical (Pythagoras would be happy). This is neither accidental nor just a convenient way of describing reality; it is inherent in the nature of reality.