Well, in general it's hard to find errors unless you have something to look for. I don't know if these should count as "screwups" since the resolution of the f

Well, in general it's hard to find errors unless you have something to look for. I don't know if these should count as "screwups" since the resolution of the flaws in each led the way to better systems, but I'd offer the following: - Infinitesimals - Hilbert's program