Re: We've been shafted again

Ah, but my point is that Barwise was just continuing the great set-theoretic illusion by making it just possible to actually do mathematics with sets instead of admitting their intellectual poverty. With a categorical foundation, these problems simply don't appear as problems. What is really wrong with traditional sets is the irrelevance of their elements. Who cares what the elements of a set really _are_? All that matters are the structures it bears and they are always expressed by functions (or relations). Michael ============================