It is also easy to see the reason why this division into two parts with its subdivision was not actually adopted here (as one might have been induced to attempt by the example of the former critique). For since it is pure reason that is here considered in its practical use, and consequently as proceeding from a priori principles, and not from empirical principles of determination, hence the division of the analytic of pure practical reason must resemble that of a syllogism; namely, proceeding from the universal in the major premiss (the moral principle), through a minor premiss containing a subsumption of possible actions (as good or evil) under the former, to the conclusion, namely, the subjective determination of the will (an interest in the possible practical good, and in the maxim founded on it). He who has been able to convince himself of the truth of the positions occurring in the Analytic will take pleasure in such comparisons; for they justly suggest the expectation that we may perhaps some day be able to discern the unity of the whole faculty of reason (theoretical as well as practical) and be able to derive all from one principle, which, is what human reason inevitably demands, as it finds complete satisfaction only in a perfectly systematic unity of its knowledge. {BOOK_1|CHAPTER_3 ^paragraph 40} If now we consider also the contents of the knowledge that we can have of a pure practical reason, and by means of it, as shown by the Analytic, we find, along with a remarkable analogy between it and the theoretical, no less remarkable differences. As regards the theoretical, the faculty of a pure rational cognition a priori could be easily and evidently proved by examples from sciences (in which, as they put their principles to the test in so many ways by methodical use, there is not so much reason as in common knowledge to fear a secret mixture of empirical principles of cognition). But, that pure reason without the admixture of any empirical principle is practical of itself, this could only be shown from the commonest practical use of reason, by verifying the fact, that every man's natural reason acknowledges the supreme practical principle as the supreme law of his will- a law completely a priori and not depending on any sensible data. It was necessary first to establish and verify the purity of its origin, even in the judgement of this common reason, before science could take it in hand to make use of it, as a fact, that is, prior to all disputation about its possibility, and all the consequences that may be drawn from it. But this circumstance may be readily explained from what has just been said; because practical pure reason must necessarily begin with principles, which therefore must be the first data, the foundation of all science, and cannot be derived from it. It was possible to effect this verification of moral principles as principles of a pure reason quite well, and with