I will believe in transubstantiation when a cracker made of wheat and a glass of wine change their molecular structure to duplicate the DNA profile of the Jewish population in the first century AD.
Until that happens, shut the hell up.
I’m not a Roman Catholic, so I had to do some research on this. Here is a document that tries to explain the Catholics Church’s position.
Basically, the problem for non-Catholics boils down to a difference in understanding about what is meant by the word SUBSTANCE. The Catholic Church uses it to describe the metaphysical properties of something, whereas others use it to describe the FORM of something. An atheist mind struggles with the notion of “the metaphysical” because for it, there is only “the physical”.
So, the substance (metaphysical properties) of Christ’s body, is manifest in the bread/wafer, and the substance (metaphysical properties) of Christ’s blood, is manifest in the wine. The Catholic Church doesn’t, as far as I know, teach that the bread and wine are TRANSFORMED into the body and blood of Christ.
The idea behind the bread and wine comes from the rites associated with the OT sacrificial system, where the flesh of the sacrifice was cut up and roasted on the alter, and the blood was sprinkled on and about it. I know it is tempting for an Atheist to imagine a slaughter house scenario, but it was more of a BBQ scenario. The majority of the sacrifices were eaten by the priests and their families, because they had no inheritance in the land.
Where the OT priests were physically sustained by the flesh of the sacrifice, NT believers are spiritually sustained by the body of Christ (bread of life). Where the offerings of the OT priests were made acceptable to God by the blood of the sacrifice, the offering of the NT believer is made acceptable to God by the blood of Christ.
It’s all got to do with acknowledgeing accountability for what we choose to do. If your transgression of the Law costs you something to repeair the rift it causes between you and God then you are less likely to do it than if it cost you nothing.
EDIT: Fixed some typos