Full Idea
We are more impressed by the fact that the special theory of relativity was used to predict the shift in the perihelion of Mercury than we would have been if we knew that the theory was constructed in order to account for that effect.
Gist of Idea
It is more impressive that relativity predicted Mercury's orbit than if it had accommodated it
Source
Peter Lipton (Inference to the Best Explanation (2nd) [2004], 10 'The fudging')
Book Reference
Lipton,Peter: 'Inference to the Best Explanation (2nd ed)' [Routledge 2004], p.172
A Reaction
Lipton has a nice discussion of the relative merits of predicting data and accommodating it. He invites astrologers to predict events, rather than accommodate past ones.
Related Idea
Idea 17403 The periodic table suggests accommodation to facts rates above prediction [Scerri]