Leonard Susskind improvisation on the uncomfortable notion of probability ;)

[dmtr]

... well, I don't really know. Uhm, I don't really know. If I had to guess, I would guess he [Einstein] was very very uncomfortable with the idea of a probabilistic theory. What does "probability" mean? You flip a coin a thousand times, what does it tell you about Nature? That the probability is 50 percent heads, 50 percent tails. Does it tell you anything about Nature? Does it, uhh, tell you that heads will turn up 500 times? No, it doesn't tell you that. Does it tell you 500 times within the margin of error, the margin of error being, what, square root of 10-30? No, it doesn't tell you that. Does it tell you that you cannot flip a thousand heads? No, it doesn't tell you that. What does it tell you? It tells you that it's "improbable" to flip ahh, a thousand heads. Well, probability is being defined in terms of probability. What ultimately does it say about Nature that, ahh, that if you flip a coin a thousand times that the probability is a heads that it will turn up - ahh, the probability is 50 percent that it will turn up heads? I think the only thing I can think that makes sense is to say you'd be very very surprised if you're outside the margin of error. It doesn't happen very often. Why doesn't it happen very often? It could happen very often, it could happen every time. Probability theory doesn't tell you that improbable things don't happen. It just tells you they're improbable; well, what does improbable mean? It just means they hardly ever happen. What do you mean they hardly ever happen, they can happen every time! Oh, but they're improbable. It doesn't say anything!!! It just says "you'd be surprised." I think Einstein was probably troubled by the idea that the most fundamental principles in physics were dependent on nothing more than what he would be surprised by. That's my guess - and I think it's Probably true.

Leonard Susskind
Lecture 9 | Modern Physics: Quantum Mechanics (Stanford)


neat ;)

[Avodyne]

"Neat" is not the word I would use. Lenny needs to brush up on his Bayesian analysis.

[fermi]

Is Susskind said these things in a lighthearted amusing chat with colleagues and graduate students over some beer and chips, that's just fine. There are lots of interesting sub-currents in there where the thread of discussion can follow. On the other hand, if he actually made these statements in a lecture hall addressing impressionable undergraduate students anxious to learn some Quantum Mechanics, he is doing disservice to Physics.

[sokrates]

what part of his argument is inaccurate?

[Neo_Anderson]

For some reason, his doctoral thesis was much more convoluted and wordy.
This thread is a premium example of the pretentousness of doctoral theses.

[Naty1]

Didn't Einstein say "God does not throw dice"? Even though he helped found quantum mechanics apparently he did not like the consequences....

[dmtr]

Didn't Einstein say "God does not throw dice"? Even though he helped found quantum mechanics apparently he did not like the consequences....

Yeah. ;) As he [Einstein] once wrote: "I find the idea quite intolerable that an electron exposed to radiation should choose of its own free will, not only its moment to jump off, but also its direction. In that case, I would rather be a cobbler, or even an employee in a gaming house, than a physicist". [Fred R. Shapiro, Joseph Epstein (2006). The Yale Book of Quotations. Yale University Press. p. 228. ISBN 0300107986.]

As to the Susskind quote, it was an informal (Q&A) part of a lecture to general public. And I see nothing wrong in it. Probability really does not have a consistent definition, and definitions that we have are in fact somewhat circular.