This conception of life, which I have given only in its barest outline, is a very common one. For thousands of years it has persisted in the philosophical field, the nourishment and the torment of the greatest intellects of humanity. But humanity could not rest satisfied with a world conceived in such a manner; with a world which, whether we call it nature or idea, is at bottom always nature. For by nature we understand not only that reality which is in space and time, but also every reality which is not the product of our will, nor the result in general of that spiritual activity, which in a manner peculiar to all human acts reveals a diversity of values, extending from the sublimity of heroism and of genius to the lowest depths of cowardice and to the gloom of sloth. Nor can it be considered as the product or result of a process; for it is immediate reality, original and immutable. In a world which is Nature, man is an intruder, a stranger without rights, without even real existence. As a being, he is destined to be suppressed; nay, he does not even exist. And his life, with all his aspirations, his needs, his claims, is but a fallacious illusion which will sooner or later collapse. Man cannot help succumbing in a world where there is no place for him. Therefore a more or less cloudy gust of pessimism lowers over the consciousness that has stopped at this conception of reality. Leopardi is the most eloquent expression of the intense misery to which man is condemned in such circumstances, or to which rather he condemns himself. He condemns himself because he has it in his power to conceive reality otherwise. For let him ponder seriously and he will succeed in convincing himself that the naturalistic conception of reality is absurd. Philosophy has so demonstrated this truth, that he who now strives eagerly to attain a moral point of view in harmony with established principles can no longer repeat that note of pessimism, can no longer assert that the world is nature, or that it is the eternal idea from which nature is derived and by which it is made intelligible. Such views are no longer tenable.