Reason in a creature is a faculty of widening the rules and purposes of the use of all its powers far beyond natural instinct; it acknowledges no limits to its projects. Reason itself does not work instinctively, but requires trial, practice, and instruction in order gradually to progress from one level of insight to another. Therefore a single man would have to live excessively long in order to learn to make full use of all his natural capacities. Since Nature has set only a short period for his life, she needs a perhaps unreckonable series of generations, each of which passes its own enlightenment to its successor in order finally to bring the seeds of enlightenment to that degree of development in our race which is completely suitable to Nature’s purpose. This point of time must be, at least as an ideal, the goal of man’s efforts, for otherwise his natural capacities would have to be counted as for the most part vain and aimless. This would destroy all practical principles, and Nature, whose wisdom must serve as the fundamental principle in judging all her other offspring, would thereby make man alone a contemptible plaything.
Nature has willed that man should, by himself, produce everything that goes beyond the mechanical ordering of his animal existence, and that he should partake of no other happiness or perfection than that which he himself, independently of instinct, has created by his own reason.
Nature does nothing in vain, and in the use of means to her goals she is not prodigal. Her giving to man reason and the freedom of the will which depends upon it is clear indication of her purpose. Man accordingly was not to be guided by instinct, not nurtured and instructed with ready-made knowledge; rather, he should bring forth everything out of his own resources. Securing his own food, shelter, safety and defense (for which Nature gave him neither the horns of the bull, nor the claws of the lion, nor the fangs of the dog, but hands only), all amusement which can make life pleasant, insight and intelligence, finally even goodness of heart – all this should be wholly his own work. In this, Nature seems to have moved with the strictest parsimony, and to have measured her animal gifts precisely to the most stringent needs of a beginning existence, just as if she had willed that, if man ever did advance from the lowest barbarity to the highest skill and mental perfection and thereby worked himself up to happiness (so far as it is possible on earth), he alone should have the credit and should have only himself to thank – exactly as if she aimed more at his rational self-esteem than at his well-being. For along this march of human affairs, there was a host of troubles awaiting him. But it seems not to have concerned Nature that he should live well, but only that he should work himself upward so as to make himself, through his own actions, worthy of life and of well-being.
It remains strange that the earlier generations appear to carry through their toilsome labor only for the sake of the later, to prepare for them a foundation on which the later generations could erect the higher edifice which was Nature’s goal, and yet that only the latest of the generations should have the good fortune to inhabit the building on which a long line of their ancestors had (unintentionally) labored without being permitted to partake of the fortune they had prepared. However puzzling this may be, it is necessary if one assumes that a species of animals should have reason, and, as a class of rational beings each of whom dies while the species is immortal, should develop their capacities to perfection.