METAPHYSICS Schopenhauer accepts from Kant that space, time, and causality are necessary and universal forms of every object, intuited in our consciousness prior to any experience Space and time are a priori forms of sensibility, and causality is an a priori form of understanding Understanding (Verstand) is not peculiar to humans, because other animals are aware of relations between cause and effect Understanding is what turns raw sensation into perception, just as the rising sun brings colour into the landscape The faculty that is peculiar to humans is reason (Vernunft), that is to say the ability to form abstract concepts and link them to each other Reason confers on humans the possibility of speech, deliberation, and science; but it does not increase knowledge, it only transforms it All our knowledge comes from our perceptions, which are what constitute the world The thesis that the world exists only for a subject leads to paradox Schopenhauer accepted an evolutionary account of history: animals existed before men, fishes before land animals, and plants before fishes A long series of changes took place before the first eye ever opened Yet, according to the thesis that the world is idea, the existence of this whole world is forever dependent on that first eye, even if it was only that of an insect Thus we see, on the one hand, the existence of the whole world necessarily dependent on the first knowing [conscious] being, however imperfect it be; on the other hand, this first knowing animal just as necessarily dependent on a long chain of causes and effects which has preceded it, and in which it itself appears as a small link (WWI 30) This antinomy can be resolved only if we move from consideration of the world as idea to the world as will The second book of The World as Will and Idea begins with a consideration of the natural sciences Some of these, such as botany and zoology, deal with the permanent forms of individuals; others, such as mechanics and physics, promise explanations of change These offer laws of nature, such as those of inertia and gravitation, which determine the position of phenomena in time and space But these laws offer no information about the inner nature of the forces of nature—matter, weight, inertia, and so on— that are invoked in order to account for their constancy ‘The force on account of which a stone falls to the ground or one body repels another is, in its inner nature, not less strange and mysterious than that which produces the movements and the growth of an animal’ (WWI 97) 170