Full Idea
Mathematicians are necessarily rational, and not necessarily two-legged; cyclists are the opposite. But what of an individual who counts among his eccentricities both mathematics and cycling?
Gist of Idea
Mathematicians must be rational but not two-legged, cyclists the opposite. So a mathematical cyclist?
Source
Willard Quine (Word and Object [1960], §41)
Book Reference
Quine,Willard: 'Word and Object' [MIT 1969], p.199
A Reaction
Quine's view is that the necessity (and essence) depends on how this eccentric is described. If he loses a leg, he must give up cycling; if he loses his rationality, he must give up the mathematics. Quine is wrong.
Related Idea
Idea 15242 Having a child is contingent for a 'man', necessary for a 'father'; the latter reflects a necessity of nature [Harré/Madden]