What is Practical Knowledge?

In this paper practical knowledge is first defined and then identified. The concept of knowledge itself is not discussed but presupposed, the paper's topic rather is what kind of knowledge is practical. 'Practical knowledge' is roughly defined as knowledge that does and shall (from a normative, prudential or moral, point of view) motivate to act in a certain way (sect. 1). After criticizing externalist (sect. 2) and inadequate internalist conceptions of practical knowledge (sect. 3), a strategy for identifying practical knowledge is exposed. One central idea of this strategy is to examine empirically the various ways of our deliberations and to choose those that are epistemically rational; the knowledge used on these ways is practical (sect. 4). As a first execution of this strategy, some elements of a decision psychology are sketched, and then some pieces of practical knowledge are identified. In particular, intrinsic value judgements are defined. The most central forms of practical knowledge, however, are value judgements that a certain action is optimum, where 'optimum' is defined in a certain internalist manner (sect. 5).