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From Eternity to Here

What could this possibly be?

It's a book I definitely would have bought at the bookstore, had not the author generously offered up a complimentary copy to readers who pledged a certain minimum in this year's Donors Choose challenge at Cosmic Variance.

I remember, many years ago, reading through Roger Penrose's The Emperor's New Mind. At the time, it was an interesting and popularly accessible read - by design, as it was a mass-market book. It combined a review of the current state of physics and computational logic, together with Penrose's own thoughts on how to explain, at a physical level, the apparent noncomputability that arises in human thought.

In 1931, Kurt Gödel published a single paper that contained what would be known as his First and Second Incompleteness Theorems. The incompleteness theorems, roughly speaking, imply that, in any sufficiently powerful formal system of logic, not all true mathematical propositions can be proven to be true within the system. Gödel's results have been discussed, folded, spindled, and multilated throughout the years, and sometimes invested with far more philosophical importance than they actually merit. But thankfully, Penrose confined his discussion to the computability aspects, although his ideas were quite controversial twenty years ago and are somewhat dated now. A pretty good discussion of the philosophical ramifications of Gödel's work can be found on Wikipedia.

From Eternity to Here, Sean Carroll

But I digress. I only brought up that book to highlight my interest (after dropping out of a physics degree and ending up in software development), in the squishier side of that wonderful subject.

Another common target for philosophical musings is the dead-obvious concept, or should I say experience, called the "arrow of time". Why do we see a egg scramble, but never jump out of the pan and reconstitute itself? Why do we remember the past, and not the future? Why does the second law of thermodynamics exist? The physics of most of the 20th century has no good explanation for this. Newton's laws, Einstein's general relativity (despite its more sophisticated definition of "time"), and even quantum mechanics are all symmetric in time. The laws look the same when you replace t by -t. So why the apparent asymmetry in our day-to-day experience? The most recent thinking starts to answer that question by positing that the universe started with very, very special initial conditions - that the arrow of time arises not from the general laws of physics, but the particulars of the universe we find ourselves in. And then there are fascinating little glimpses of things like CP violation in Ko meson decay, which seem to imply the Standard Model knows just a little, teeny tiny bit about the arrow of time.

This new book tackles those sorts of issues head-on, with some of the best that modern, 2000s-era academic thought has to offer. I'm looking forward to breaking it open later tonight.

Besides, with the great quotes from rock-star reviewers like Penrose and Kip Thorne, how could I not want to read it?