Thursday, 29 December 2011

Hume on Scepticism Part II

Greetings to my fellow readers and bloggers. I hope you all had a good Christmas, I managed to watch Lohengrin an intriguing mix of styles between the Ring cycle and Parsifal. Indeed Lohengrin is in fact Parsifal's son. Which may raise a few eyebrows as Parsifal in the opera devoted to him has commited himself to celibacy. Still consistency was never a strong point of mythology. Those who don't know Lohengrin should get to know it.  Act II is the best, the music looking forward to the Ring Cycle. Anyway this is not the main point of the post, which is to finish off my examination of Hume's scepticism.

Recall that Hume is arguing for a mitigated scepticism which recognises the limits of Human Knowledge, we saw in the first post on this that one of the benefits of Hume's scepticism is that it would avoid dogmatism. The other benefit Hume sees is that it will act as a brake on speculative philosophy by acknowledging that there are limits to what philosophy or any branch of human knowledge can achieve and we should take care to recognise speculation for what it is and concentrate on problems which we can actually solve.

It seems to me that Hume's lesson needs to be taken on board in a number of areas not least in some developments of physics. There is an interesting tension, on the one hand given Heisenberg's uncertainty principle  and Godel's theorem. we seem to be acknowledging that even our most rigorous methods of obtaining knowledge about the world have severe limitations, something which Hume would be delighted to

On the other hand some aspects of modern physics do seem to border on the realms of speculation to which
there can be no testable consequences. I refer of course to the speculation that seems rife in quantum physics such as  Many Worlds theories and also that attempts to quantise gravity seem to be inherently untestable.

Readers of earlier posts will know that I tend to view claims that the wavefunction in quantum physics as a real field with a healthy degree of scepticism. The simplest explanation of it's role is as a mathematical device for generating the probabilites of quantum effects to occur. Thus when a measurement occurs the wave function does not physically collapse, all that happens is that one of the possibilities is realised. This pragmatic and slightly unromantic view of the situation cuts out all the speculation associated with what for want of a better word is the mystical or science fiction interpretation of quantum mechanics. The Many worlders would agree with me that the wavefunction does not physically collapse, but they would argue (if I understand it correctly) that because the wavefunction is a real field every time a measurement is made the wavefunction splits creating another universe, but of course we have no means of communication with that other universe.
(How convenient),   If that is one of the prices one has to pay for seeing the wavefunction as a real field then I'm afraid it's not worth it. By definition such a hypothesis is untestable and therefore cannot be good science as it is 'Not even wrong'.

A similar criticism could be made of the current attempts to quantise gravity. Indeed such a criticism has been made of superstring theory by Peter Woit.

I first read this book about 6 years ago. In it he argues that superstring theory is inherently untestable as the methodology used there does not lead to anything which can be tested in the lab. For example it's not clear that it does contain the standard model of particle physics as a lower limit. In this it is quite different from say quantum physics or relativty which do reduce to Newtonian physics in the limit. Woit rightly in my opinion criticises the amount of money that has been spent on such research.
Woit has devoted a blog which challenges the claims of those who would over exaggerate the importance
of areas of research such as superstrings.

And I recommend it to my readers as an antidote to all the hype about modern physics one consistently gets in the media.

Part of the problem, it would seem is that superstrings and the mystical/science fiction interpretation of quantum mechancis seem to tap into some part of the human pschye for a modern form of mysticism. Well fine, but don't claim that this is real science and certainly don't expect the taxpayer to fund your lifestyle.

Why not admit that superstrings or many worlds theories are speculations, that quantum physics far from being a mystery is in fact a well developed tool for predicting the behaviour of atomic, molecular and nuclear systems with applications to astrophysics, particle physics, chemistry and other fields. There is more than enough awe and wonder to be found in the day to day applications of science to solve currently intractable problems and given that one can go out and test such applications I would have thought more rewarding.     

I'll let Hume have the last word, here he is referring to the typical 'proofs' current in his time, that the Supreme Being is actively causing everything (even my finger movements over the keyboard as I type this post).

"Though the chain of arguments, which conduct to it, were ever so logical, there must arise a strong suspicion, if not absolute assurance, that it has carried us quite beyond the reach of our faculties, when it leads to conclusions so extraordinary, and so remote from common life and experience. We are got into fairy land."

It seems to me that talk of many worlds or us living in a world of 10,11 or 26 dimensions is just as likely to have led us into fairy land as anything else.


No comments:

Post a Comment