matt (hbergeronx) wrote,

feed pimping and a quote

I'm going to pimp two LJ feeds, because I think people would benefit from them.

First: unapologetic_fd, which is not only an excellent math resource but also general-interest interesting. I'm particularly impressed by his criticism of Pi day.

Second: notevenwrong_fe, the blog from the book. I was astounded by the number of people at the atheist meeting I want to a while back who went "ooh, string theory, leonard susskind, smart people talking over my head, anthropic principle" {spooge} and I'm determined not to fall into the "believing things just because smarter people than me believe them" trap, which IMO defeats the whole point of being an atheist/skeptic. It's tough work to decide to be your own person, and it's not for everyone. I don't look down on people who don't choose to follow that path, there are some really quite decent ready-baked philosophies that are much easier and more reliable than bake-your-own. Not everyone *should* be baking their own.

That said, if anyone can pimp feeds or LJ users which might be interesting along these lines, I'd be grateful. I'm trying to get a good sound basis in practical group theory, particularly for nefarious purposes, so resources in that direction are especially desirable.

Finally, a quote:

There are two ways to teach quantum mechanics. The first way -- which for most physicists today is still the only way -- follows the historical order in which the ideas were discovered. So, you start with classical mechanics and electrodynamics, solving lots of grueling differential equations at every step. Then you learn about the "blackbody paradox" and various strange experimental results, and the great crisis these things posed for physics. Next you learn a complicated patchwork of ideas that physicists invented between 1900 and 1926 to try to make the crisis go away. Then, if you're lucky, after years of study you finally get around to the central conceptual point: that nature is described not by probabilities (which are always nonnegative), but by numbers called amplitudes that can be positive, negative, or even complex.

Today, in the quantum information age, the fact that all the physicists had to learn quantum this way seems increasingly humorous. For example, I've had experts in quantum field theory -- people who've spent years calculating path integrals of mind-boggling complexity -- ask me to explain the Bell inequality to them. That's like Andrew Wiles asking me to explain the Pythagorean Theorem.

As a direct result of this "QWERTY" approach to explaining quantum mechanics - which you can see reflected in almost every popular book and article, down to the present -- the subject acquired an undeserved reputation for being hard. Educated people memorized the slogans -- "light is both a wave and a particle," "the cat is neither dead nor alive until you look," "you can ask about the position or the momentum, but not both," "one particle instantly learns the spin of the other through spooky action-at-a-distance," etc. -- and also learned that they shouldn't even try to understand such things without years of painstaking work.

The second way to teach quantum mechanics leaves a blow-by-blow account of its discovery to the historians, and instead starts directly from the conceptual core -- namely, a certain generalization of probability theory to allow minus signs. Once you know what the theory is actually about, you can then sprinkle in physics to taste, and calculate the spectrum of whatever atom you want.

-- PHYS 771 lecture , Scott Aaronson, from here

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