In the fifteenth century, technology (the crafts) was doing better than either natural philosophy or the sciences in producing works that still have something to say to the twenty-first century. We may contrast Brunelleschi's dome for Florence cathedral (still standing) with contemporary theories of the motion of the Sun (which could not correctly predict dates of equinoxes). Craftsmen, whose activities were attracting increasing attention from the learned, had much to teach scholars about the power of approximate, non-rigorous methods and the usefulness of focussed observation.