Kant and the straight biangle
pp. 226-234
in: Enno Rudolph, Ion-Olimpiu Stamatescu (eds), Philosophy, mathematics and modern physics, Berlin, Springer, 1994Abstract
In the framework of his critical philosophy, Kant, as is well known, felt obliged to adopt a position with regard to the problem of the foundations of geometry. One of the ways in which he did this was to consider whether the concept of a straight biangle was consistent or involved a contradiction. Kant then entangled himself in a striking difficulty, which, however, appears to have been noted by few. To my knowledge, the only other person who has as yet seen it is Gottfried Martin2 and his proposed solution is also the only one that I yet know.
