Practical reason is the general human capacity for resolving, through reflection, the question of what one is to do. Deliberation of this kind is practical in at least two senses. First, it is practical in its subject matter, insofar as it is concerned with action. But it is also practical in its consequences or its issue, insofar as reflection about action itself directly moves people to act. Our capacity for deliberative self-determination raises two sets of philosophical problems. First, there are (...) questions about how deliberation can succeed in being practical in its issue. What do we need to assume — both about agents and about the processes of reasoning they engage in — to make sense of the fact that deliberative reflection can directly give rise to action? Can we do justice to this dimension of practical reason while preserving the idea that practical deliberation is genuinely a form of reasoning? Second, there are large issues concerning the content of the standards that are brought to bear in practical reasoning. Which norms for the assessment of action are binding on us as agents? Do these norms provide resources for critical reflection about our ends, or are they exclusively instrumental? Under what conditions do moral norms yield valid standards for reasoning about action? The first set of issues is addressed in sections 1-3 of the present article, while sections 4-5 cover the second set of issues. (shrink)

René Descartes (1596-1650) is widely regarded as the father of modern philosophy. His noteworthy contributions extend to mathematics and physics. This entry focuses on his philosophical contributions in the theory of knowledge. Specifically, the focus is on the epistemological project of Descartes' famous work, Meditations on First Philosophy.