The problem for the philosopher is to discover a meaning in this senseless current of human actions, so that the history of creatures who pursue no plan of their own may yet admit of a systematic form.  The clew to this form is supplied by the predispositions of human nature.

I have stated this problem almost in Kant’s words, and as he might have stated it if he had not introduced the conception of final causes.  His use of the postulate of final causes without justifying it is a defect in his essay.  He identifies what he well calls a stream of tendency with “a natural purpose.”  He makes no attempt to show that the succession of events is such that it cannot be explained without the postulate of a purpose.  His solution of the problem is governed by this conception of finality, and by the unwarranted assumption that nature does nothing in vain.

He lays down that all the tendencies to which any creature is predisposed by its nature must in the end be developed perfectly and agreeably to their final purpose.  Those predispositions in man which serve the use of his reason are therefore destined to be fully developed.  This destiny, however, cannot be realised in the individual; it can only be realised in the species.  For reason works tentatively, by progress and regress.  Each man would require an inordinate length of time to make a perfect use of his natural tendencies.  Therefore, as life is short, an incalculable series of generations is needed.

The means which nature employs to develop these tendencies is the antagonism which in man’s social state exists between his gregarious and his antigregarious tendencies.  His antigregarious nature expresses itself in the desire to force all things to comply to his own humour.  Hence ambition, love of honour, avarice.  These were necessary to raise mankind from the savage to the civilised state.  But for these antisocial propensities men would be gentle as sheep, and “an Arcadian life would arise, of perfect harmony and mutual love, such as must suffocate and stifle all talents in their very germs.”  Nature, knowing better than man what is good for the species, ordains discord.  She is to be thanked for competition and enmity, and for the thirst of power and wealth.  For without these the final purpose of realising man’s rational nature would remain unfulfilled.  This is Kant’s answer to Rousseau.

The full realisation of man’s rational nature is possible only in a “universal civil society” founded on political justice.  The establishment of such a society is the highest problem for the human species.  Kant contemplates, as the political goal, a confederation of states in which the utmost possible freedom shall be united with the most rigorous determination of the boundaries of freedom.