[21] He also assumes a society not only of rational intelligences determined by the same rational motives, but equal in ability to carry out their motives. (See my article in Mind [new series, Vol. XI, No. 42, p. 162], reprinted in the volume dedicated to William James, by the Philosophical Faculty of Columbia University.)
[22] Surefootedness, or certainty in thinking and in acting seems to have been the chief desideratum at which Kant aimed. As against scepticism or mere empirical groping this element of the inner life is obviously of exceeding value. But it is far from being the only element to be taken into account.
[23] See the more extended remarks on this subject in Book III.
[24] In Kant’s view the rational element is projected on the irrational. In this way spatial juxtaposition is ideally transformed into a spatial continuum. In the same manner temporal sequence is ideally changed into a uniform temporal flux. Without the former, geometry could not have established its propositions; without the latter Galileo could not have measured the fall of the stone.
[25] The ethical character of acts depends on the worth of the agent and the object. Is it right to kill or to enslave a fellowman? We do not hesitate to kill an animal, or to harness horses to vehicles, or to use them as beasts of burden. Why not kill men, or use them as beasts of burden in like manner?—Only because they possess a worth which gives them a different standing.
Is it on grounds of sympathy that I should observe the so-called moral rules? But if I am not sympathetic by nature, why should I be subject to censure in case I refrain from displaying a tenderness which I do not feel? Why should I sympathize with the pleasures and pains of fellow human beings any more than with the pleasures and pains of inferior sentient creatures, unless men have worth? And worth, as will appear in the subsequent chapters, signifies indispensableness in a perfect whole. No detached thing has worth. No part of an incomplete system has worth. Worth belongs to those to whom it is attributed in so far as they are conceived of as not to be spared, as representing a distinctive indispensable preciousness, a mode of being without which perfection would be less than perfect.
So that morality depends on the attribution of worth to men, and worth depends on the formation in the mind of an ideal plan of the whole—or instead of a complete plan let me say more precisely a rule of relations whereby the plan is itself progressively developed.
[26] To rate anyone as an end per se means that in a world conceived as perfect his existence would be indispensable. The world we know may not be perfect, is not perfect, but we do conceive of an ideal world that is. And to ascribe to anyone the quality of worth, to denominate him an end per se, is to place him into that world, to regard him as potentially a member of it.
[27] For a creature endowed with different senses, and having a mind unlike our own, the world would be a totally different world.
[28] To deny such a priori knowledge of the object called God is not to deny that the production of this object is due to constructive principles of human thinking; while, in turn, to assert the functional derivation of the God-idea is not to validate that idea itself as permanent and inexpugnable. It may have owed its origin to a permanent disposition of the mind, and yet be fallible because of the historical conditions under which it arose and the defective data in which it was expressed. By way of illustration we might apply the same reflection to the Ptolemaic astronomy. The mathematical processes by which this astronomy was constructed may be traced to permanent singularities of human thinking, yet the astronomical theory of Ptolemy is not on that account a priori true.