(1.) _The Analytic._—Freedom, as the one constituent element which shows itself in the activity of our will, is the simple _form_ of our actions. The universal law binding the will, is that it should determine itself purely from itself, independently of every external incitement. This capacity of self-lawgiving, or self-determining, Kant calls the _autonomy of the will_. The free autonomic will says to man: thou oughtest! and since this moral ought commands to an unconditioned obedience, the moral imperative is a _categorical imperative_. What is it now which is categorically commanded by the practical reason? To answer this question, we must first consider the empirical will, _i. e._ the nature-side of man. The empirical, as the other constituent element of our will, first produces a definite deed when it has filled the empty _form_ of action with the _matter_ of action. The matter of the will is furnished by the sensory in the desire of pleasure and the dread of pain. Since this second principle of our actions does not find its seat in the freedom of the will as the higher faculty of desire, but in the sensory, as the lower faculty of desire, and a foreign law is thus laid upon the will,—Kant calls it, in opposition to the autonomy of the reason, the _heteronomy of the will_. The categorical imperative is the necessary law of freedom binding upon all men, and is distinguished from material motives, in that the latter have no fixed character. For men are at variance in respect of pleasure and pain, since that which is disagreeable to one may seem pleasant to another, and if they ever agree, this is simply accidental. Consequently, these material motives can never act the part of laws binding upon every being, but each subject may find his end in a different motive. Such rules of acting, Kant calls _maxims_ of the will. He also censures those moralists who have exalted such maxims as universal principles of morality. Nevertheless, these maxims, though not the highest principles of morality, are yet necessary to the autonomy of the will, because they alone furnish for it a content. It is only by uniting the two sides, that we gain the true principle of morality. To this end the maxims of acting must be freed from their limitation, and widened to the form of universal laws of the reason. Only those maxims should be chosen as motives of action which are capable of becoming universal laws of the reason. _The highest principle of morality_ will therefore be this: act so that the maxims of thy will can at the same time be valid as the principle of a universal lawgiving, _i.e._ that no contradiction shall arise in the attempt to conceive the maxims of thy acting as a law universally obeyed. Through this formal moral principle all material moral principles which can only be of a heteronomic nature, are excluded.