The Catholic doctrine of transubstantiation comes from the council of Trent (although that simply defines what the RCC believes), and that is based upon the articulation of this doctrine by Aquinas, and that is based upon
Aristotelian substance theory, which states that when we strip away the accidents of a particular thing we are left with its substance, which cannot be observed. Aquinas uses this to state that the accidents of our senses’ perception of the bread and wine don’t change, but God changes the substance of those things to be the actual body and blood of Christ.
Here’s the problem: No one actually embraces Aristotelian substance theory any more. It has fallen victim to the developments of science in our understanding of the universe and the actual substance of matter and energy. The “accidents” are actually a reflection of how the atoms and subatomic particles interact and not some unseen substance. “Substance”, it seems, is nothing more than the subjective (although roughly agreed upon within a given language) idea behind a given term that we apply to a category of items. Nothing more.
And yet the Church continues to embrace transubstantiation as its explanation for the bread and wine being the actual body and blood of Christ.
How does the RCC deal with this? Their doctrine is based upon a universally rejected ontology.
Let me make a few comments, coming late. First, this topic has been discussed many times in this Forum and in others here. I’ve commented several times. First you have to understand that the Dogma of the Church on Transubstantiation is tied neither to science nor to any particualr philosophy but to the clear teaching of Christ Himself and to that teaching as it has been held by the Tradition of the Church, which can be found in the comments of the early Church Fathers and as historically taught by the Church.
However, the Church found it convenient to use the understanding of Substance and Accident as taught by Thomas Aquinas to convey the language of the Dogma, which defines Her belief and that of all faithful Catholics.
In the Church’s teaching, the " accidents " of the bread and wine remain without a substance in which to inhere after the Consecration. Of course these " accidents " can be detected with ease by normal observation and in detail by scientific tests. The accidents have not changed - all physical attributes that make bread to be bread and that make wine to be wine are still present. Science would say that nothing has happend to the substance of either, since all the identifying attributes are still present.
But science has never defined what it means by " substance. " All science has ever dealt with are the accidents of things - those things which can be touched and measured in some way.
It is philosophy which has defince substance as that in which accidents inhere and that which inheres in nothing else itself. It is that particular thing which exists beneath all the detectible accidents ( and here there is some room for discussion, since philosophers have indeed differed on the exact, precise meaning.). We can also say that it would include the form which makes a thing to be a particular type of thing, since a thing must have both existence and form or it is nothing ( we could now go to the current thread " Aristotle’s notion of substance " for more discussion on these points ).
It is enough to know that at the Consecration a miracle takes place, actually several.
The substance of the bread and wine is turned into the substance of Christ’s body and blood. In other words the substances of the bread and wine ( which we cannot see ) are changed into the substance of Christ’s body and blood, which we cannot see, **and **
all the accidents of Christ’s body and blood as well. Not only this but the entire glorified Christ is physically present
under/beneath/behind each species - both the bread and the wine, and this by concomitence as Thomas says.
So all arguments about science disagreeing with what the Church teaches really doesn’t mean a thing, since the Church gets her teaching from Christ himself and uses the language of Aquinas to try to help make the miracle understandable - as far as possible.
I hope this helps explain the Church’s teaching.
So remember that " substance " was and has always been a philosophical term and is still used by Catholic Philosophers and Theologians today. Science has grabed the term and put it to its own use. Science cannot now tell us we do not use the term correctly. That seems a bit unfair. Hadn’t we better say that traditional Aristotelian and Thomistic Philosophy and the Catholic Church use the term in its most original and basic way and that Science has extrapolated and changed the meaning of the term because it was convenient. And no, the Church will not change its teaching, though perhaps some day it may elaborate more by trying to make the teaching more clear - but I wouldn’t wait for that.
Linus2nd