IV. MODALITY.
The Permitted and the Forbidden
Duty and the contrary to duty.
Perfect and imperfect duty.
BOOK1|CHAPTER2 ^paragraph 40
It will at once be observed that in this table freedom is considered as a sort of causality not subject to empirical principles of determination, in regard to actions possible by it, which are phenomena in the world of sense, and that consequently it is referred to the categories which concern its physical possibility, whilst yet each category is taken so universally that the determining principle of that causality can be placed outside the world of sense in freedom as a property of a being in the world of intelligence; and finally the categories of modality introduce the transition from practical principles generally to those of morality, but only problematically. These can be established dogmatically only by the moral law.
I add nothing further here in explanation of the present table, since it is intelligible enough of itself. A division of this kind based on principles is very useful in any science, both for the sake of thoroughness and intelligibility. Thus, for instance, we know from the preceding table and its first number what we must begin from in practical inquiries; namely, from the maxims which every one founds on his own inclinations; the precepts which hold for a species of rational beings so far as they agree in certain inclinations; and finally the law which holds for all without regard to their inclinations, etc. In this way we survey the whole plan of what has to be done, every question of practical philosophy that has to be answered, and also the order that is to be followed.