Looking twice at the history of science

Friday, June 20, 2014

Saving the symmetry principle V: symmetry without skepticism

To save the symmetry principle it is not enough to separate that principle from its false companions, as I have tried to do so far in this series. It is also necessary to show that adherents of the principle are likely to write better histories of science than those who flout it. In the previous post I defined the Symmetry Principle as the view that we should not reason from the truth or falsity of a belief to the goodness or badness of the believer's reasons for holding the belief. The best defense of this principle is simply to observe that sometimes past scientists have been right for the wrong reasons and wrong for the right reasons. But there's a problem with this defense: it seems to lead to radical skepticism about present-day science. In this post I want to show how we can accept the Symmetry Principle without abandoning present-day science or erecting artificial barriers between scientists and historians. Expand post.


  1. Part of this post seems to orbit the "pessimistic induction" argument. Much as I like the rest of the series, I never found pessimistic induction at all convincing.

    Simply put, evidence accumulates over time. For Descartes or Kepler to believe in the instantaneous propagation of light: quite reasonable. For someone nowadays to believe it: well, skipping a page of qualifications, they'd have to be nuts.

    A quick question for you: what do you get from the Symmetry Principle that you don't get from the warning, "Watch out for the Fixed Evidence Fallacy!"?

    I'll give my own answer later on in a separate comment.

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