Marsilio Ficino’s Platonic Theology, Volume II

2But I suppose you will divide them after the manner of mathematicians, into all the parts they can have. You will therefore cut both sight and color into infinitely many particles, and each part of sight will sense a corresponding portion of color. There will thus be countless acts of sight, countless colors seen, and countless visions. In this way a single color could never meet the sight without infinitely many acts of sight seeing infinitely many colors, and seeing them infinitely, at that very moment. This cannot even be imagined. Perhaps, to avoid these monstrosities, we shall suppose that the whole faculty of sight senses, while its parts do not. But this too is rash. How could things devoid of sensation generate a substance that senses? They could not. Parts incapable of sensing will therefore not constitute the faculty of sensation itself. Shall we say instead that every part of sight senses, yet that all do so through the same complete vision belonging to the whole faculty; and that each senses the whole form and the parts together with the whole? No. First, it is not the form that is seen, but the color itself through the form. Second, an operation produced by assembling distinct parts is also produced through an accumulation of moments and is completed gradually; sensation, however, occurs at once, which shows that the power of sensing is indivisible. Finally, if every part of sight is by itself sufficient for seeing, what need is there of several? If it is not sufficient, does something sentient arise from what does not sense? Unless, perhaps, those parts are gathered into one by some higher sentient power. But that power will be the soul and the faculty of sensation itself. We shall therefore never escape these deranged answers so long as we affirm that sensation is divisible. Let sensation, then, be impartible; and let the soul be such as well, since it is both the source and the subject of indivisible power.