19. When things enter into the matter that plays the part of mother to them, they neither hurt it, nor give it pleasure. Their blows are not felt by matter; they direct their blows only against each other, because the powers act upon their opposites, and not on their substrates, unless indeed we consider the substrates as united to the things they contain. Heat makes cold disappear,[92] as whiteness affects blackness; or, if they mingle, they produce a new quality by their mixture.[93] What is affected is the things that mingle, and their being affected consists in ceasing to be what they were. Among animate beings, it is the body that is affected by the alteration of the qualities, and of the forces possessed. When the qualities constitutive of these beings are destroyed, or when they combine, or when they undergo some change contrary to their nature, the affections relate to the body, as the perceptions do to the soul. The latter indeed knows all the affections that produce a lively impression. Matter, however, remains what it is; it could not be affected when it ceases to contain heat or cold, since neither of these qualities is either characteristic or foreign. The name that best characterizes matter, therefore, is nurse or residence.[94] But in what sense could matter, that begets nothing, be called "mother"? Those who call it such consider a mother as playing the part of mere matter, towards her child, merely receiving the germ, without contributing anything of itself, because the body of the child owes its growth to nourishment. If however the mother does contribute anything (to the formation of the child) she then plays the part of form, and does not restrict herself to the part of matter. Indeed, the form alone is fruitful, while the "other nature" (that is, matter), is unfruitful. THE MYTH OF THE ITHYPHALLIC HERMES. That no doubt was the meaning of those ancient sages who in mysteries and initiations symbolically represented the "ancient Hermes"[95] with the generative organ in erection, to teach that it is intelligible reason that begets sense-objects. On the other hand, these same sages signify the sterility of matter, condemned to perpetual self-identity, by the eunuchs who surround Rhea,[96] making of it the mother of all things, to use the expression they employ in designating the principle that plays the part of substrate. THE STERILITY OF NATURE INDICATED BY CASTRATION.