 Horwich’s core idea is that our acceptance of sentences is governed by certain laws, and, in the case of non-ambiguous expressions, there is a single “acceptance regularity” which explains all of our uses of the expression. The type of acceptance regularity which is relevant will vary depending on the sort of expression whose meaning is being explained. For example, our use of a perceptual term like “red” might be best explained by the following acceptance regularity: