Hi,
The Catholic Church does not see inanimate objects like bread and wine as being spiritual in themselves. It uses substance in a philosophical way in that a substance is seen as that which is essential to what a thing is. Accidents, on the other hand, are those parts of things that are not essential to making the thing what it is, even though they may enhance it. Accidents are such things as weight, height, color, fragrance and so forth.
When one bakes a loaf of bread, the activity of yeast changes a damp blob of dough into a light, tender loaf. An interior change has taken place within the dough itself. Certainly, there has been a change in its’ accidents. It is lighter and its’ color has changed. But more importantly, due to the activity of the yeast, the lump of dough is essentially no longer what it was. It has undergone a substantial change; it is no longer dough, but bread.
This is what happens with the Eucharist. The substance of the bread and the substance of the wine change into the body and blood of Jesus Christ. But the appearances (accidents) remain the same. So they feel, look and smell the same. We only know about the change by our faith in what Jesus has revealed to us about it. This is what we mean by transubstantiation.
Fr. Vincent Serpa, O.P.
