I'm facing an embarrassing attribution mystery: I really like a quote, and I'm hoping to use it in some of my writing, but I don't know whom to attribute it to! (Maybe one of you wrote it?) Here's the passage I found in my collection of miscellaneous ideas and quotations related to my blog (unfortunately lacking any indication of where I lifted the passage from): The freedom of mathematics is that we can define conceptual structures of all kinds, as long as the rules governing them are clear and free of contradiction. [(The preceding sentence was in my article on tropical semirings.] And even when two such structures seem to be incompatible, there is often a way of viewing them together. This is simplest when the two systems are nested one inside the other, the way the real number system sits inside the tropical semiring (whichever one you like), which in turn sits inside the extended real number line. But even in cases where the two systems seem incompatible, like Euclidean two-dimensional geometry and non-Euclidean two-dimensional geometry, there is typically a higher point of view that reconciles them. If we insist on a literal point of view of what math is telling us, then we can't believe in both Euclidean geometry and non-Euclidean geometry; they appear to be making contradictory assertions about space. But that's an example of what Buddhist teacher Alan Watts called eating the menu instead of the dinner. Once we understand that geometrical postulates and theorems are making assertions about the possibilities of the notion of space, and not about the physical space we inhabit, then we can see a context in which Euclidean and non-Euclidean geometry, far from being mutually undermining, are in fact mutually supporting. I tried Googling the opening sentence, but it's not in the Google database. It's possible that parts of this are mine and parts aren't. But I strongly suspect that the sentence about Alan Watts isn't mine, since I've never read anything by Alan Watts (though I have read books by people who quote, Alan Watts, so who knows?). Jim Propp