Human: I have a question about Kant’s Critique of Dialectical Reason. Where does he say that the categories are a priori? Assistant: 
In the first part of the Critique of Pure Reason, he says that the categories are a priori in the way that the senses are a priori. The categories are the basic concepts that we use to understand the world. For example, the category of substance is the concept of something that exists independently of our minds. The category of causality is the concept of something that causes other things to happen.