 There are a couple of possibilities about what Collins has in mind for numerical powers. One is that numerical powers would include both powers that conform to the Composition Principle (figure and motion), and powers that do not (the power of the eye to see). Generical powers, by contrast, simply treat powers that are numerically different (such as different kinds of motion) just as motions. Thus, all material powers, treated as generical, conform to the Homogeneity Principle (Clarke 1738 [1928: 806–807]; Clarke and Collins 2011: 28–30).