 Instead of seeing this “adding to” as evidence for the disunified view, the mixed-mathematics view understands Hobbes having seen certain disciplines as providing causal principles (what he called the ‘why’) while other disciplines provided the facts relevant to a given domain (what he called the ‘that’). Textual support for this understanding of Hobbes’ system can be found in Hobbes’ methodological statements about natural philosophy as well as in his practice of explanation.