physics as metaphysics

I don't recommend reading Leonard Susskind's new book, but I do recommend reading this review of it:

I was eager to learn how, in the end, Susskind and company showed that Hawking was probably wrong — that information is indeed conserved. But first I had to get through a 66-page crash course on relativity and quantum mechanics. Every book about contemporary physics seems to begin this way, which can be frustrating to anyone who reads more than one. (Imagine if every account of the 2008 presidential campaign had to begin with the roots of Athenian democracy and the heritage of the French Enlightenment.)

Finally we get to the heart of the story, and it turns out to be a mind-bender. To make sense of Hawking’s paradox one must consider how much information, measured in bits, the 1s and 0s of binary code, can fit inside a black hole. The amount, it turns out, does not depend on the black hole’s volume, as one might expect, but on the area of its “horizon” — the flat, funnel-like mouth of the cosmic rabbit hole.

Susskind explains this dizzying notion about as clearly as is probably possible. Every time a bit falls into a black hole, its opening expands by one square Planck length — an area billions and billions of times smaller than a proton. It is because of this phenomenon, Susskind contends, that the information isn’t lost. A description of everything that falls into a black hole, whether a book or an entire civilization, is recorded on the surface of its horizon and radiated back like imagery on a giant drive-in movie screen. As with a hologram, three dimensions are contained within two.

Strangest of all, we learn, this holographic conjecture — elevated in the book, perhaps prematurely, to the holographic principle — may apply to the entire universe. Hence the notion of our own reality as an illusory projection of some flatlanders’ membrane world. It’s as though the pixilated people we see on television are real and the actors are only secondary manifestations.

Oh, the actors are only secondary manifestations? I see now.