

For a brief, but pretty detailed account, try Hempel's _Philosophy of
Natural Science_.


This smacks a bit of ideology -- the supposition being that Toricelli's
subsequent descriptions of his reasoning are not veridical.  It gets dangerously
close to an unfalsifiable view of the history and methodology of science if
we deny that no subsequent reports of experimenters are reliable descriptions
of their "real" reasons.


But my point is that this type of case is *not* a rarity.  In fact, I was
going to point to Pasteur as yet another rather common example -- particularly
the studies on spontaneous generation and fermentation.  I will readily
concede that "ridiculous reasons" can play an important role in how
scientists spend their time.  But one should not confuse motivation with
methodology nor suppose that ridiculous reasons provide the impetus in the
majority of cases based on relatively infrequent anecdotal evidence.