Categorical Imperative. A term used by Kant in his Critique of the Practical Reason, to denote its à priori absolute and universal pronouncement in favour of moral good and duty. It is à priori, and therefore independent of prudential considerations, which can only be the result of experience, and being à priori it is necessary and universal. This is a fundamental truth in morals, and rests on what Kant calls the autonomy of the will (see Autonomy). It is plain, however, that this categorical imperative can only apply to the general ideas of right and duty, or to cases which unmistakably come under the express commandment of God, and the consent of the Catholic conscience.
In cases where an honest mind may be in doubt, cases involving contingent considerations, and mixed up with circumstances peculiar to themselves, the judgment must be exercised. When it is conscientiously exercised, with of course a faithful recourse to all means within reach of arriving at a right decision, the resulting conduct may admit of question, but the man has done right. The fiat of conscience, as has been well observed, is not do this but be this. In a doubtful case we are to determine as we best may whether doing this does or does not come under the head of being this.