 In fact the vast majority of concepts—house, reptile, tree—are mere adventitious collections of things that are formulated in response to practical needs, and thus cannot, however exact the results of the corresponding science, attain to truth or knowledge. Nor do the concepts of mathematics escape the ‘pseudo’ tag. What Croce calls pure concepts, in contrast, are characterised by their possession of expressiveness, universality and concreteness, and they perform their office by a priori synthesis (this accounts for character mentioned above). What this means it that everything we can perceive or imagine—every representation or intuition—will necessarily have all three: there is no possible experience that is not of something concrete, universal in the sense of being an instance of something absolutely general, and expressive, that is, admitting of verbal enunciation. Empirical concepts, then, like heat, are concrete but not universal; mathematical concepts, like number, are universal but not concrete. Examples of pure concepts are rare, but those recognized by Croce are finality, quality and beauty. Such is the domain of Logic, in Croce’s scheme.