Thursday, December 28, 2006

Uncertain about Heisenberg

In a comment at Woit's Not Even Wrong, Paul Jackson points to this essay by E. Prugovecki, which is about the less-than-solid foundations - both mathematical and philosophical - of modern physics, in particular, quantum field theory.

There are many things to examine in that essay. However, for now, I look at a quote from Heisenberg that Prugovecki actually uses twice!

Quote 1:

And, in a similar vein, Heisenberg (1971) comments: If predictive power were the only criterion of truth, Ptolomy's astronomy would be no worse than Newton's.

Quote 2:

...but as Heisenberg acerbicly pointed out on one occasion, if predictive power were indeed the only criterion for truth, Ptolemy's astronomy would be no worse than Newton's (Heisenberg, 1971, p. 212).

The reference is : Heisenberg, W.: 1971, Physics and Beyond, Harper and Row, New York

To produce Newton's astronomy, we need his three laws of motion and the law of gravitation. The laws of motion are of great generality and describe non-gravitational phenomena as well (e.g., a lot of today's civil and mechanical engineering is included) Leaving that aside, Newton's laws describe bodies falling at the earth's surface, as well as the motions of planets, and the motions of their satellites. One also finds Newton's laws adequate, e.g., for galactic motions - general relativistic corrections are small. Ptolemy has nothing to say about anything but the planets. Just on predictive power, Newton's astronomy is infinitely superior to Ptolemy's.

So, I disagree with Heisenberg's remark, as presented in Prugovecki's essay. Heisenberg, no doubt, knew all of what I just wrote, and that is what leads to my feeling of uncertainty. What did he mean?