Popper on Why Explanation Seems Improbable

Popper did not believe we could explain the success of our attempt to explain things. He said:

no theory of knowledge should attempt to explain why we are successful in our attempts to explain things.

Even if we assume that we have been successful–that our physical theories are true–we can learn from our cosmology how infinitely improbable this success is: our theories tell us that the world is almost completely empty, and that empty space is filled with chaotic radiation. And almost all places which are not empty are occupied either by chaotic dust, or by gases, or by very hot stars–all these in conditions which seem to make the application of any method of acquiring physical knowledge logically impossible.

To sum up, there are many worlds, possible and actual worlds, in which a search for knowledge and for regularities would fail. And even in the world as we actually know it from the sciences, the occurrence of conditions under which life, and a search for knowledge, could arise–and succeed–seems to be almost infinitely improbable. Moreover, it seems that if ever such conditions should appear, they would be bound to disappear again, after a time which, cosmologically speaking, is very short.

Objective Knowledge, p. 23

Later on, he makes this more explicit:

[Of the explainability of reality we can have] no assurance of any kind. …it certainly does not depend uon the metaphysical and most likely false assumption that the true structural theory of the world (if any), is discoverable by man, or expressible in human language.

If the picture of the world which modern science draws comes anywhere near to the truth…then the conditions of obtaining almost everywhere in the universe making the discovery of structural laws of the kind we are seeking–and thus the attainment of ‘scientific knowledge’–almost impossible. For almost all regions of the universe are filled by chaotic radiation, and almost all the rest by matter in a similarly chaotic state. In spite of this, science has been miraculously successful in proceeding towards what I have suggested should be regarded as its aim [of finding explanations about reality.]This strange fact cannot, I think, be explained without proving too much. But it can encourage us to pursue that ai8m, even though we may not get any further encouragement to believe that we can actually attain it…

Objective Knowledge, p. 203-204

This view stands in stark contrast to Deutsch’s view which turns things around to nearly the opposite, namely how he predicts (in FoR p. 350) the non-existence of heat death because that would contradict our theory that the universe is explainable.

I admit I’m not entirely convinced by Deutsch’s argument. I wish it was stronger. But I’d much rather believe in an infinite explicable universe than a finite one.

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