 For one thing, this process looks a great deal like mathematical reasoning. For Locke, moral rules are founded on a fundamental set of principles, much like mathematical axioms. The fundamental principles can be deduced rationally, and it is from these that we can further derive all of our moral duties. Morality is, therefore, demonstrable, a term indicating mathematical-style proofs wherein conclusions are derived from axiomatic foundations. The moral status of any action is then determined by comparing our behaviour against these demonstrated rules. But, we might ask, what kinds of ideas are moral ideas, and what sort of rationalist could Locke possibly be? Locke is a well-known empiricist; for Locke, the mind is a blank slate, the content of which is supplied exclusively from sensory or reflective experience. Locke famously espouses this empiricist view in the Essay, but holds it quite clearly also in the Essays on the Law of Nature. In fact, however, Locke’s moral rationalism takes this empiricist theory of ideas as its starting point. Moral ideas, for Locke, are fundamentally experiential in origin. They are not directly so, of course, since we do not perceive something like justice or honesty directly. Moral ideas are experiential, in the special Lockean sense that they are complex ideas—products of the mind’s ability to form complex constructions from its simple directly-experiential contents. For Locke, the interplay of reason and sensation works as follows: