I have been trying and failing to explain the Eucharist to an atheistic physicalist, which should be no surprise in and of itself, what I am worried about is that I am missing something very simple in my definition of the Eucharist. The problem he has is when I state that the bread and wine become literally the body, blood, soul and divinity.
Below for reference please find his replies:
Let me say quite clearly that I’m perfectly open to the logical possibility of non-material substance. I can make sense of the idea and I see no contradiction in supposing that non-material substance exists. (I doubt that there is any non-material substance, but that is another matter.) Each individual mind has often been thought of as a non-material substance (e.g., substance dualism of Descartes and others. There are even a few contemporary atheistic philosophers who endorse substance dualism.)
Now to the problem. The rub is that it is said that the wine (a kind of physical substance) changes into another kind of physical substance (blood), but without changing any of its physical properties. If that is what is being said, I cannot see how that can possibly be true. The essence of a kind of physical substance (wine, blood, etc.) is precisely those physical properties that make it that kind of physical thing. If those properties do not change, it cannot change from one kind of physical substance to another. Conversely, to change what it is physically (from wine to blood, say) it must change those physical properties that make it wine to those physical properties that make it blood. Otherwise, it would not literally be blood. And yet it is said that none of physical properties change. There’s the rub.
On the other hand, you seem to want to say is that it is not the physical substance that changes but the “metaphysical substance”. But what is the metaphysical substance of, say, blood, over and above its physical substance? What is the essence of blood, in the nature of blood, over and above it physical essence and its physical nature? If you can provide any insight answering that, I think I would be a lot closer to being able to understand your views.
To be as clear as I can, my objection is not based on denying the existence of non-material metaphysical substance – I am happy to allow non-material substance as a metaphysical possibility; it is based on the difficulty of reconciling a) the wine literally becomes blood with b) it changes none of its physical properties. I can perfectly well understand that idea that a non-material substance (say, Jesus) comes to be literally and fully present in the wine. That is no more (or less) metaphysically puzzling that saying souls inhabit or are “united with” bodies. But you seem to want to say something much more: that the wine becomes blood without changing any physical properties. Blood, Jesus’ or anyone’s, if understood literally, is a physical substance, anything that is blood has the essential physical properties of blood.
Where our disagreement may be located, I suspect, is in you saying that you believe in metaphysical substance over and above physical substance. But for a physical object they are one and the same thing. “Metaphysical substance” is a covering concept for any kind of substance, be it physical or mental or spiritual whatever. A thing’s metaphysical substance is whatever it is that constitutes the nature or essence of that thing whatever kind of thing that happens to be. For a physical kind of thing (blood, wine, bread, flesh, etc.) it’s metaphysical substance is its physical substance, just as we might say of a spiritual entity that its metaphysical substance is its non-material substance (its soul). Metaphysical substance is not something that a physical object has over and above its physical substance, precisely because it is a physical object. My physical body, for example, is a complex physical substance. Its metaphysical substance simply is nothing more or less than its physical substance. There is nothing more or less to my body than a physical thing – it is metaphysically, a physical substance. If, however, I am essentially a soul rather than a body, then my essence and nature – my metaphysical substance – lies in some non-physical substance (my soul, say). In principle, two substances – one physical and the other non-physical – can inhabit the same space, but my soul is no part of the metaphysical substance of my body, nor vice versa.
Going back to the Eucharist, if you want to say that the spirit of Jesus (which presumably would be of the essence of Jesus and constituting his metaphysical substance) is literally and fully present in the wine and bread, I can make perfect sense of that. The problem comes when you say that the wine become Jesus’ blood. Interpreted literally, that cannot be without a change in physical properties – those properties that make a difference between something being wine or being blood.
One further option occurs to me. Perhaps you will insist that the essence of Jesus is not exclusively non-physical but is essentially physical as well. Jesus cannot be Jesus without being physical as well as non-physical. If that is really what you want to say that the logical contradiction would be manifest, since no thing can be essentially physical and non-physical.