Schopenhauer opens this supplementary volume by insisting that the intellect is subordinate to the will, a claim he supports through a striking natural analogy. Observing insects in autumn—some spinning cocoons, others laying eggs before dying—he argues that death and sleep are not radically different. The insect that dies is identical in essence to the one hatched in spring, just as the man who goes to sleep is the same as the one who wakes. This metaphor of the leaf and the tree recurs throughout the chapter, with Schopenhauer addressing a hypothetical foolish leaf that laments its fall, unaware that it shares its nature with the tree's future leaves.

The Intellect as Servant

In Chapter XXI, Schopenhauer characterizes the intellect as subordinate, a tool of the will. He writes that without this subordination, “everything which takes place without it” would be inexplicable. The intellect, he claims, is not the primary driver of action but a secondary faculty that serves the will's ends. This view contrasts with rationalist traditions that place reason at the center of human agency. Schopenhauer's language is direct: the intellect is “of a subordinate nature,” a claim he reinforces by pointing to instinctual behaviors in animals and humans that operate without conscious deliberation. The chapter's title, “Retrospect and More General View,” signals that he is stepping back to synthesize earlier arguments, but his focus remains on the will's primacy.

Nature's Doctrine of Immortality

Schopenhauer's meditation on insects leads to what he calls “nature's great doctrine of immortality.” He observes the care with which an insect prepares a cell, deposits an egg, and dies, comparing it to a man laying out clothes for the next morning before sleep. The insect's death, he argues, is no more final than sleep, because the true nature of the insect persists in the egg and the following spring's hatchling. He extends this to humans: the future generations are not created from nothing but exist already in the present, in the “real” that is always present. The leaf that laments “I am not these! These are quite different leaves!” is mistaken, for it fails to recognize its identity with the tree's ongoing life. Schopenhauer's rhetoric here is both poetic and philosophical, using the cycle of seasons to challenge linear notions of birth and death.

The Questioner Rebuked

Schopenhauer directly addresses a hypothetical questioner who asks where future generations come from. The answer is a rebuke: “Where else should they be than there where alone the real always was and will be, in the present and its content?” The questioner, he says, is like the foolish leaf, mistaking his own nature. The passage culminates in a Greek quotation from Homer—οἱη περ φυλλων γενεη, τοιηδε και ανδρων (“as is the generation of leaves, so is that of men”)—tying his argument to classical literature. This rhetorical strategy, blending philosophical assertion with literary allusion, is characteristic of Schopenhauer's style. He does not prove his point through empirical evidence but through analogy and the force of his prose, challenging the reader to recognize the will's persistence beyond individual existence.

Readers approaching this volume should note that it is a supplement, not a standalone work; Schopenhauer frequently refers back to arguments from the first two books. The excerpts show his method: building a philosophical case through vivid natural imagery and direct address to the reader. Pay attention to how he uses metaphors—the leaf, the insect, the tree—to make abstract claims about the will tangible. His tone is urgent, even combative, as he insists on the identity of the individual with the species.