Just as perceptions arranged sensations around objects in space and time, so conception arranges perceptions (objects and events) about the ideas of cause, unity, reciprocal relation, necessity, contingency, etc.; these and other “categories” are the structure into which perceptions are received, and by which they are classified and moulded into the ordered concepts of thought. These are the very essence and character of the mind; mind is the coördination of experience.
