4. Then again, we find that there is the same sense and feeling of cold as of heat; but privation is neither to be seen, heard, or felt, neither is it known to any of the other senses. For the object of sense is substance; but where no substance appears, there we understand privation to be,—which is a negation of substance, as blindness of sight, silence of voice, and vacuity of corporeal substance. For there is no sense or perception of vacuity by feeling; but where there is no body to be felt, there a vacuity is implied. Neither do we hear silence; but where we do not hear any thing at all, there we imply silence. In like manner we have no perception of blindness, nakedness, or being unarmed; but we know them from the negation of our sense. Therefore if cold were a privation of heat, there would be no being sensible of cold; but only where heat ceased to be, there cold would be implied. But if, as heat is perceptible by the warmth and laxative softness of the flesh, so cold is no less perceptible by the contraction and condensation of it, it is from thence apparent, that there is some peculiar original and fountain of cold as well as heat. 5. Further then, privation of every kind is something single and simply particular; but in substances there are several differences and efficacies. For silence is a thing but of one sort; but of sounds there are great variety, sometimes molesting, sometimes delightful to the sense. There are also the same differences in colors and figures, which vary as they occur to the senses. But that which is not to be felt, which is without color and void of quality, can never be distinguished, but is always like itself. 6. Is cold therefore to be numbered among those privations that are not distinguished in their action? Rather the contrary, in regard that pleasures very great and beneficial to our bodies arise from cold things; as no less terrible mischiefs, pains, and stupefaction on the other side; which the heat does not always avoid and give way to, but many times enclosed within the body, withstands and opposes. Which contention of theirs is called quivering and shaking, at what time, if the cold overcome the heat, thence proceed numbness and stiffness of the limbs; but if the cold be vanquished by the heat, there follow a pleasing warmth and opening of the skin, which Homer expresses by the word ἰαίνεσθαι. These things are past dispute; and chiefly by these passive qualities it is, that we find cold to be opposite to heat, as substance to substance, or passive quality to passive quality, not as negation or privation; neither is it the destruction or abolishing of hot, but a kind of nature and power tending to its destruction. Otherwise we should exempt the winter out of the seasons, and the north winds out of the number of the winds, as being privations of the warmer seasons and the southern gales, and not having any proper original.