It does not happen to often, but once in a great while I run into the cannibalism argument against the Eucharist from Protestants. It is an interesting argument, but if the person you are talking with actually accuses Catholics of practicing cannibalism, then it demonstrates that he at least understands the seriousness with which we say that Jesus is truly present in the Blessed Sacrament, even if he does get the particulars wrong. So, what do we respond when somebody attacks the Holy Eucharist on the ground that to eat the flesh and drink the blood of Jesus would be cannibalism?
Leviticus 17:14 seems to categorically prohibit the eating of flesh with the blood or the drinking of the blood of any creature:
For the life of all flesh is in the blood. Therefore I said to the children of Israel: you shall not eat the blood of any flesh at all, because the life of the flesh is in the blood, and whosoever eateth it, shall be cut off.
(anima enim omnis carnis in sanguine est unde dixi filiis Israhel sanguinem universae carnis non comedetis quia anima carnis in sanguine est et quicumque comederit illum interibit)
If this commandment applies, then, so runs the argument, the Eucharist cannot truly be the Body and Blood of our Lord, for to consume it would be against what God commanded in Leviticus, and thus God is made to contradict Himself. What do we say to this?
Well, there are two explanations, one satisfactory, one (in my opinion) more unsatisfactory. We shall look at the less satisfactory of the two defenses to this charge first.
This defense comes from Dr. Scott Hahn (I do not recall where exactly I heard him give this explanation, but I believe it was on a radio call-in show). According to Dr. Hahn, the response to the Protestant charge of cannibalism is "Guilty as charged!" Hahn does not deny that we eat the Body and Blood of our Lord, and therefore asserts that the Eucharist truly is cannibalism. What else could it be if the Eucharist is truly the Body and Blood of our Lord, and cannibalism means eating human flesh and drinking human blood, which the Eucharist us: consuming the flesh and blood of a Divine Human. What about the fact that Leviticus specifically says that whoever does this shall be "cut off" from God's covenant?
Dr. Hahn says that by partaking of the flesh and blood of Christ we do, in fact, want to "cut" ourselves off from the Old Covenant. In accepting the flesh and blood of the God-Man, we implicitly renounce adherence to the Old Covenant, which forbid cannibalism. Christ took upon Himself the curse of the Old Covenant, and we too must accept that "cutting off" from the Old Covenant to be truly accepted into the New. Therefore, we take upon ourselves the reprobation of the Old Covenant which was reserved to those who ate and drank blood by doing the very thing which God prohibited under the Old Law.
Huh? Well, I guess it makes sense a little bit, but it is novel. I prefer the older, more precise Scholastic explanation. This brings us to our second defense, which I think is more sound:
Cannibalism is defined as eating the flesh of one's own species under the form of flesh. What do I mean "under the form of flesh?" Well, if I eat a man, say, part of his leg or arm, then I am committing cannibalism: I am eating human flesh under the form of flesh. But, let's say that a shark eats a man. The man is digested and becomes part of the shark. Then, a week later, some fishermen catch the shark, kill it and turn it into shark steaks. Then we eat the shark. Are we committing cannibalism? No. But aren't we consuming human flesh when we eat the shark which has eaten the man? Yes, but not under the form of flesh. The flesh of the man has been broken down and is not longer under that form anymore. Therefore, though in a way it can be said that we are eating human flesh when we eat the shark, we are certainly not committing cannibalism.
Now, in the Eucharist, we eat the flesh and blood of Jesus Christ under the forms of bread and wine. No flesh is consumed in the form of flesh. Therefore, flesh and blood are truly consumed, but there is no cannibalism. I think this is a better (and simpler) explanation than Dr. Scott Hahn's. Hahn's explanation does not deny the charge of cannibalism and makes up a far-flung and complicated theological reason why it is okay, while the second simply reduces the matter to a confusion over the meaning of the term "cannibalism."