Critique of Practical Reason
Duty! Sublime and mighty name that embraces nothing charming or insinuating but requires submission, and yet does not seek to move the will by threatening anything that would arouse natural aversion or terror in the mind but only holds forth a law that of itself finds entry into the mind and yet gains reluctant reverence (though not always obedience), a law before which all inclinations are dumb, even though they secretly work against it; what origin is there worthy of you, and where is to be found the root of your noble descent which proudly rejects all kinship with the inclinations, descent from which is the indispensable condition of that worth which human beings alone can give themselves?
FUNDAMENTAL LAW OF PURE PRACTICAL REASON: So act that the maxim of your will could always hold at the same time as a principle in a giving of universal law.
Two things fill the mind with ever new and increasing admiration and reverence, the more often and more steadily one reflects on them: the starry heavens above me and the moral law within me.
[H]ow can that mean be called quite free at the same point of time and in regard to the same action in which and in regard to which he is nevertheless subject to an unavoidable nature necessity? It is a wretched subterfuge to seek to evade this by saying that the kind of determining grounds of his causality in accordance with natural law agrees with a comparative concept of freedom (according to which that is sometimes called a free effect, the determining natural ground of which lies within the acting being, e.g., that which a projectile accomplishes when it is in free motion )
These postulates are not theoretical dogmas but presuppositions having a necessarily practical reference and thus, although they do not indeed extend speculative cognition, they give objective reality to the ideas of speculative reason in general (by means of their reference to what is practical) and justify its holding concepts even the possibility of which it could not otherwise presume to affirm.
Readers' Notes allow users to add their own analysis and insights to our SparkNotes—and to discuss those ideas with one another. Have a novel take or think we left something out? Add a Readers' Note!