 As noted above, the Meditations contains a destructive component that Descartes likens to the architect’s preparations for laying a foundation. Though the component finds no analogue in the methods of geometers, Descartes appears to hold that it is needed in metaphysical inquiry. The discovery of Euclid’s first principles (some of them, at any rate) is comparatively unproblematic: such principles as that things which are equal to the same thing are also equal to one another accord not only with reason, but with the senses. In contrast, metaphysical inquiry might have first principles that conflict with the senses: