 Much of the epistemology of artifacts is, in the first instance, the province of cognitive psychology, not philosophy. Artifact kinds, for instance, can be approached from the side of psychology rather than metaphysics, yielding theories about the psychological mechanisms by means of which we group artifacts together, apart from any question of whether these groupings represent reality (Malt &amp; Sloman 2007a). In an influential article, Paul Bloom (1996) argues that we cannot categorize artifacts based on form, use, or function. Form and use are both too variable to be reliable. Beanbag chairs do not look much like other chairs, and even if every flatiron in existence were currently being used as a doorstop, we would not want to categorize them as doorstops. Experiments show that even intended function is neither necessary nor sufficient for categorization (Malt &amp; Johnson 1992). Vary the form of something sufficiently, and people will decline to categorize it as a chair even if it is made to be sat on. On the other hand, present them with something that looks like a chair but is made to be a plant stand, and they will still categorize it as a chair. In response, Bloom proposes an intentional-historical theory, according to which categorization of artifacts depends on our being able to infer that an artifact was successfully made with the intention that it belong to a particular category. Form and use are good grounds for such inferences, and this explains our intuition that these factors have something to do with how we categorize artifacts. So if something looks like a chair and we regularly observe people sitting on it, we reasonably infer it was made with the intention that it be a chair, and we categorize it accordingly. (Bloom’s view is clearly ancestral to Amie Thomasson’s account of artifact kinds  (Section 2.2),  but he is concerned only to explain how we group artifacts, and does not claim, as Thomasson does, that makers’ intentions and concepts are ontologically constitutive of artifact kinds.) Barbara Malt and Eric Johnson (1998) criticize Bloom for failing to make clear either why we would need to resort to creator’s intention to categorize artifacts, or exactly how we might assess that intention. More recently, Malt and Steven Sloman (2007a; 2007b) have argued that the kind of essentialist approach represented by Bloom’s theory is misguided, and have proposed an alternative, pragmatic approach. In a series of experiments, they show that artifact categorization is sensitive to communicative goals in specific situations. Creators’ intentions are important with regard to some goals and situations; unimportant with regard to others. If this approach is on the right track, artifact kinds are not psychologically stable or clearly demarcated groupings. Moreover, this raises the possibility that “categorization” itself is not a psychological natural kind. It may be that this label is used for what is actually a heterogeneous collection of processes.