Kant

Kant starts off making two distinctions regarding kinds of knowledge, empirical/rational and formal/material. Empirical or experience-based knowledge is contrasted with rational knowledge, which is independent of experience. This distinction between empirical and rational knowledge rests on a difference in sources of evidence used to support the two different kinds of knowledge. Formal is contrasted with material knowledge. Formal knowledge has no specific subject matter; it is about the general structure of thinking about any subject matter whatsoever. Material knowledge is of a specific subject matter, either nature or freedom. Rational knowledge is metaphysics, of which there are two branches, the metaphysics of nature and of morals. The metaphysics of nature is supposed to provide rational knowledge of the laws of nature. These are not empirical laws; they are more like universal principles of nature that any empirical physical would presuppose, such as that no event in nature occurs without a natural cause. The metaphysics of freedom is supposed to provide knowledge of the laws of freedom. These are the universal rules, which free agents devise to govern them. Thus, Kant's grounding, his initial attempt at a critique of rational reason, is an investigation of the possibility of purely rational knowledge of morals. Take, for example, the Moral Rule: Thou shalt not lie. If the moral law is valid as the basis of moral obligation or duty, then it must be necessary. Kant using the word "necessity" means that the rule obligates or binds whatever the conditions or in all circumstances. It also means that the rule applies to all rational beings and not only to human beings. In this second sense we can say that the rule is universally binding. So in fact, moral rules are universal and necessary. If a moral rule is to be universal and necessary, the moral law must be derived from concepts of pure reason alone. Therefore, if a moral rule or law can only be derived from reason alone, there must be a pure moral philosophy whose task is to provide such a derivation. In the "Grounding", Kant sets himself the task of establishing the "supreme principle of morality" from which to make such a derivation. According to Kant good will and only a good will is intrinsically good. Kant distinguishes two different types of intrinsic or extrinsic goods. If a thing is only extrinsically good, then it is possible for that thing not to be good, or to be bad or evil. Intrinsic goodness is goodness in itself; if a thing is intrinsically good, its goodness is essential to it; and