A young mathematician asks for the hand of a senior mathematician's beautiful (and clever) daughter, but is refused on the grounds that his inability to support her financially was a mathematical certainty. His only hope is to demonstrate to the older gentleman contrary to his claims regarding the certainty of math, that "figures lie". And, that he does in a clever way, by showing that even though the computations in the father's astronomical tables are mathematically accurate, in at least one instance they fail to describe the reality of the universe (as understood in the best theories of the time).
Thanks to Vijay Fafat for pointing out this story, originally published in Waterloo's book "The Wolf's Long Howl", now available for free at Google Books.
