Transubstantiation goes a ways further into explaining exactly what is going on than simply saying that, though.
From
EWTN's explanation of the concept:
Besides the Real Presence which faith accepts and delights in, there is the doctrine of transubstantiation, from which we may at least get a glimpse of what happens when the priest consecrates bread and wine, so that they become Christ's body and Christ's blood.
At this stage, we must be content with only the simplest statement of the meaning of, and distinction between substance and accidents, without which we should make nothing at all of transubstantiation. We shall concentrate upon bread, reminding ourselves once again that what is said applies in principle to wine as well.
We look at the bread the priest uses in the Sacrament. It is white, round, soft. The whiteness is not the bread, it is simply a quality that the bread has; the same is true of the roundness and the softness. There is something there that has these and other properties, qualities, attributes- the philosophers call all of them accidents. Whiteness and roundness we see; softness brings in the sense of touch. We might smell bread, and the smell of new bread is wonderful, but once again the smell is not the bread, but simply a property. The something which has the whiteness, the softness, the roundness, has the smell; and if we try another sense, the sense of taste, the same something has that special effect upon our palate.
In other words, whatever the senses perceive-even with the aid of those instruments men are forever inventing to increase the reach of the senses- is always of this same sort, a quality, a property, an attribute; no sense perceives the something which has all these qualities, which is the thing itself. This something is what the philosophers call substance; the rest are accidents which it possesses. Our senses perceive accidents; only the mind knows the substance. This is true of bread, it is true of every created thing. Left to itself, the mind assumes that the substance is that which, in all its past experience, has been found to have that particular group of accidents. But in these two instances, the bread and wine of the Eucharist, the mind is not left to itself. By the revelation of Christ it knows that the substance has been changed, in the one case into the substance of his body, in the other into the substance of his blood.
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And it goes on like this for quite some time, making philosophical statements about this or that.
It is interesting to me, for the purposes of drawing a distinction between this kind of explanation and what you can find in the Orthodox liturgical texts of my own Church ("the sanctification is by the Holy Spirit" -- period), how much transubstantiation relies on the knowledge and acceptance of these philosophical categories, without which nothing can be made of the doctrine at all (according to the above). After all, the piece starts off noting that this is all "besides the real presence", so this is something
additional to the basic belief that Christ is truly present in the bread and wine, which is not a point of difference between the Roman Catholics and the Orthodox.
From having been RC and now not being so (I suppose to the those of the Chalcedonian confession such as yourselves it's a matter of opinion as to whether or not I am Orthodox now; I will continue to write in this manner in defense of my Church regardless), I think you could say that about a lot of things that distinguish Roman Catholicism and Orthodoxy: the question of their differences is not usually at the level of
what they are talking about (e..g, in this case, the Eucharist or the real presence of Christ in it or whatever you want to call it), but of
how they talk about it. As I wrote in my earlier reply, I don't see why any of this is necessary at all, as it wouldn't even occur to me to make the kinds of distinctions or statements that to Roman Catholics quite reasonably underlie what they say about their faith. "Accidents", "substance", "properties"....er, okay, then. You have a good time with that. I'm gonna be over here, doing this:
And while I'm doing this, I'm going to be giving the responses from the section of the liturgy I already presented ("Amen, I believe", etc.), which is what my faith requires, so that we all know in a crystal clear and
experiential fashion what it is we are engaging in and why. We prostrate here before the holy body and blood of Christ our God, present before us, and given for us for the remission of sins and for eternal life. Philosophical arguments may have their place (I guess...for other people in other traditions), but that place is not here, and not now.
Respectfully, that is the difference. There is a great deal of philosophy underlying RC ideas about many subjects that quite simply has no place in other traditions, and that is why you end up with these differences that maybe you cannot see as differences because they are ingrained in the way you talk about something, even something that we both agree on at a different level of discussion. They are not similarly ingrained in other peoples' faith.
