 Knowledge of “matching” is knowing how to correctly distinguish, or identify, the kind of thing to which a name refers. This is the sort of practical know-how that the blind man lacks. Early Mohist epistemology seems to have focused on this form of knowledge to the exclusion of the preceding two. The later Mohists also seem to have taken this as their primary focus, since as we saw above they explain both perceptual knowledge and understanding as an ability to match names with things by describing them (A5) or sorting them into kinds (A6). (Clearly, though, a person could learn a good deal about sorting into kinds merely on the basis of knowing names.) The fourth type of knowledge, knowledge of acting, is knowing how to act correctly—probably, given the context, knowing how to respond appropriately to the sort of thing denoted by a particular name or term. That this is included in a categorization of the objects of zhī (knowledge) underscores the theoretical unity of knowledge and action for the Mohists. Cognition and practical wisdom, or knowing what to do and when to do it, are both considered aspects or forms of zhī (knowledge). 