A week ago, we had a very interesting Physics department colloquium by
Marcelo Gleiser about his recent book,
A Tear at the Edge of Creation: A Radical New Vision for Life in an Imperfect Cosmos.
He discussed his growing disillusion with string theory and the search for a "theory of everything" which is based on the predominance of symmetry. He gave important examples of symmetry breaking in nature including CP violation in the electro-weak interactions [which because of the CPT theorem implies time reversal invariance] and the unique chirality of amino acids in proteins.
Although it was a nice talk I thought it was all a bit sad to see someone who had become so enamoured with the propaganda of the reductionism in the high-energy physics community that it was painful when doubts emerged. Most of the points Gleiser was making seem to me to have been made long ago (in a more constructive sense) by Anderson in his 1972 "More is Different" article in Science, and more passionately and more recently by Laughlin in A Different Universe.
I did not see the point / problem with the existence of broken symmetries in nature. In any finite group there will be operations that are not a symmetry. The fact that CP is not a symmetry seems less profound (or at least, no more profound) than the fact that CPT IS a symmetry.
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