Wednesday, December 17, 2014

Philosophy and Science: Physicist George Ellis' Comments on Krauss, Hawking, and Tyson

Back in July of 2014 John Horgan interviewed George Ellis for Scientific American.  Ellis is a physicist-mathematician-cosmologist who co-authored the 1973 work The Large-Scale Structure of Space-Time with Stephen Hawking.  The full interview is worth reading but here are a few fascinating excerpts with specific reference to the need for philosophy to undergird good science and what happens when bad philosophy enters the scientific enterprise.  NOTE: All bold-face type is added by me.

Horgan: Lawrence Krauss, in A Universe from Nothing, claims that physics has basically solved the mystery of why there is something rather than nothing. Do you agree?
Ellis: Certainly not.  He is presenting untested speculative theories of how things came into existence out of a pre-existing complex of entities, including variational principles, quantum field theory, specific symmetry groups, a bubbling vacuum, all the components of the standard model of particle physics, and so on. He does not explain in what way these entities could have pre-existed the coming into being of the universe, why they should have existed at all, or why they should have had the form they did.  And he gives no experimental or observational process whereby we could test these vivid speculations of the supposed universe-generation mechanism. How indeed can you test what existed before the universe existed? You can’t.
Thus what he is presenting is not tested science. It’s a philosophical speculation, which he apparently believes is so compelling he does not have to give any specification of evidence that would confirm it is true. Well, you can’t get any evidence about what existed before space and time came into being.  Above all he believes that these mathematically based speculations solve thousand year old philosophical conundrums, without seriously engaging those philosophical issues. The belief that all of reality can be fully comprehended in terms of physics and the equations of physics is a fantasy. As pointed out so well by Eddington in his Gifford lectures, they are partial and incomplete representations of physical, biological, psychological, and social reality.
And above all Krauss does not address why the laws of physics exist, why they have the form they have, or in what kind of manifestation they existed before the universe existed  (which he must believe if he believes they brought the universe into existence). Who or what dreamt up symmetry principles, Lagrangians, specific symmetry groups, gauge theories, and so on? He does not begin to answer these questions.
It’s very ironic when he says philosophy is bunk and then himself engages in this kind of attempt at philosophy. It seems that science education should include some basic modules on Plato, Aristotle, Kant, Hume, and the other great philosophers, as well as writings of more recent philosophers such as Tim Maudlin and David Albert.

Horgan: Krauss, Stephen Hawking and Neil deGrasse Tyson have been bashing philosophy as a waste of time. Do you agree?
Ellis: If they really believe this they should stop indulging in low-grade philosophy in their own writings. You cannot do physics or cosmology without an assumed philosophical basis. You can choose not to think about that basis: it will still be there as an unexamined foundation of what you do. The fact you are unwilling to examine the philosophical foundations of what you do does not mean those foundations are not there; it just means they are unexamined.
Actually philosophical speculations have led to a great deal of good science. Einstein’s musings on Mach’s principle played a key role in developing general relativity. Einstein’s debate with Bohr and the EPR paper have led to a great of deal of good physics testing the foundations of quantum physics. My own examination of the Copernican principle in cosmology has led to exploration of some great observational tests of spatial homogeneity that have turned an untested philosophical assumption into a testable – and indeed tested – scientific hypothesis. That’ s good science.