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 its goodness is not a
function of factors other than itself. Kant holds that only a good will, not
happiness, is intrinsically good. The idea that it is reason rather than natural
impulse which guides action for the sake of happiness is false. Parts of a
person perform their functions by surviving and this provides happiness for the
person. Reason functions poorly in serving that purpose; instinct does better
job. Natural instinct rather than reason provides better for happiness. Kant
distinguishes between having a reason to act and acting for a reason. The
motivating reason is the reason for which agent acts. A justifying reason is the
reason that justifies, warrants, provides the criterion of rightness for the
action. The agent's motivating reason might or might not provide a justifying
reason for his action. Kant then defines three types of motivating reasons. One
type of non-moral motivation is natural motivation. Action in accord with duty
is motivated by immediate or direct inclination. Direct inclination includes
such motives as love, sympathy, instinct for self-preservation, or the desire
for happiness. The other type of non-moral motivation is prudence. An action in
accord with duty, but motivated by prudence, is action motivated by the pursuit
of self-interest or happiness. Since all human beings naturally desire
happiness, prudential motivation is indirectly motivated by a natural
motivation. Moral motivation is the third type of motivation. The action is not
only in accord with duty, but motivated by duty, done from duty, or for sake of
duty. The agent's motivating reason, the reason for which he acts, is that the
action is what morality demands and he wants above all to do what reason
demands.