The Summary of Physics Restored

177It is probable that the power of multiplication present in the seeds of things flows from heavenly form as its efficient cause, rather than from elemental matter. For multiplication is an activity especially proper to light: from one ray of light almost infinitely many are poured out and multiplied without end. Hence the Sun, the immortal source of light, is also Nature’s first efficient cause of generation and multiplication. A very strong argument that every natural form receives its power of multiplying from heavenly light, of which it is a ray, is that form, endowed with its ancestral gifts, is luminous and therefore multiplying. It is luminous because its brilliance illuminates the sensitive and imaginative faculties in animals. From these two faculties arises a twofold apprehension and knowledge of things: outward through the senses, inward through imagination. All knowledge is light, just as ignorance is darkness. A certain illumination and clarity arise when images of things are apprehended, and what lay unknown in darkness is revealed through the light of acquaintance. For obscure things are disclosed by the gift of light alone. To the human being God added a third light, namely intellect, through whose aid a far more perfect knowledge of things through their causes is gained. All these effects are produced by the action of light and transparency flowing from the luminous soul. This last activity of light belongs to human beings alone; the preceding two are shared with the other animals, whose souls also participate in heavenly light. Reason therefore establishes that the power of multiplication in individual animals, and indeed plants, proceeds from the soul as it multiplies light. Certain rays of that soul are enclosed in the seed together with the ethereal spirit and hidden there until, with the rising of the Sun of life, they are at last made manifest.