Quality

Two kinds of qualities must be distinguished; the essential quality, which is a peculiarity of its being, and the mere quality, which affects the being’s classification. The mere quality introduces no change in the essence, and causes none of its characteristics to disappear; but, when the being exists already, and is complete, this quality gives it a certain exterior disposition; and, whether in the case of a soul or body, adds something to it. Thus visible whiteness, which is of the very being of white lead, is not of the being of the swan, because a swan may be of some color other than white.

Therefore it follows that the accidents continue in this sacrament without a subject. This can be done by Divine power: for since an effect depends more upon the first cause than on the second, God Who is the first cause both of substance and accident, can by His unlimited power preserve an accident in existence when the substance is withdrawn whereby it was preserved in existence as by its proper cause, just as without natural causes He can produce other effects of natural causes, even as He formed a human body in the Virgin's womb, "without the seed of man" (Hymn for Christmas, First Vespers).

And, indeed, we here understand by modes the same with what we elsewhere designate attributes or qualities. But when we consider substance as affected or varied by them, we use the term modes; when from this variation it may be denominated of such a kind, we adopt the term qualities [to designate the different modes which cause it to be so named]; and finally, when we simply regard these modes as in the substance, we call them attributes. Accordingly, since God must be conceived as superior to change, it is not proper to say that there are modes or qualities in him, but simply attributes; and even in created things that which is found in them always in the same mode, as existence and duration in the thing which exists and endures, ought to be called attribute, and not mode or quality.

So that if any one will examine himself concerning his notion of pure substance in general, he will find he has no other idea of it at all, but only a supposition of he knows not what SUPPORT of such qualities which are capable of producing simple ideas in us; which qualities are commonly called accidents. If any one should be asked, what is the subject wherein colour or weight inheres, he would have nothing to say, but the solid extended parts; and if he were demanded, what is it that solidity and extension adhere in, he would not be in a much better case than the Indian before mentioned who, saying that the world was supported by a great elephant, was asked what the elephant rested on; to which his answer was—a great tortoise: but being again pressed to know what gave support to the broad-backed tortoise, replied—SOMETHING, HE KNEW NOT WHAT.

As a result of transubstantiation, the species of bread and wine undoubtedly take on a new signification and a new finality, for they are no longer ordinary bread and wine but instead a sign of something sacred and a sign of spiritual food; but they take on this new signification, this new finality, precisely because they contain a new "reality" which we can rightly call ontological. For what now lies beneath the aforementioned species is not what was there before, but something completely different; and not just in the estimation of Church belief but in reality, since once the substance or nature of the bread and wine has been changed into the body and blood of Christ, nothing remains of the bread and the wine except for the species—beneath which Christ is present whole and entire in His physical "reality," corporeally present, although not in the manner in which bodies are in a place.