 Although philosophy, as an empirical enterprise, is itself bound by experience, this is not a defect in the science of human nature. The same is true for all the sciences: “None of them can go beyond experience, or establish any principles which are not founded on that authority” (T Intro 10). Explanations must come to an end somewhere. When we see that we have “arriv’d at the utmost extent of human reason, we sit down contented”, for the only reason we can give for our most general principles is “our experience of their reality” (T 9).