Having laid out the general shape and conduits of the mind, Freud goes on to elucidate the forces that act within that structure—namely, the love instinct and the death instinct. The former is the tendency to create; the latter, the tendency to destroy. He props up his argument for these forces by appealing to cosmology and by implicitly invoking ideas of entropy and Newton's third law of motion (that of equal and opposite forces): “the task of death instinct is to lead organic matter back to the inorganic state; on the other hand... Eros aims at more far-reaching coalescence of the particles into which living matter has been dispersed” (56). Besides this purely aesthetic reasoning, Freud gives no further argument for the existence of these two opposing instincts—save to (parenthetically) mention "anabolism and katabolism" (56), the cellular processes of building up and breaking down molecules.