I put the following question to Francis Beckwith via e-mail:
Thomas Aquinas and Spinoza both hold that there is exactly one God. Would you say that when they use Deus they succeed in referring to one and the same God, but just have contradictory beliefs about this one and the same God? When I put this question to Dale Tuggy in his podcast discussion with me, he bit the bullet and said Yes to my great surprise.
Professor Beckwith responded:
. . . I am accepting what each faith tradition (at least in its orthodox formulations) believes about God: he is the self-existent subsistent source of all that receives its being from another. Does that include Spinoza’s God? Yes, with a caveat. He has the right God but the wrong universe. He gets the self-existent subsistent source right, but he gets that which receive its being from another wrong. It’s the univocal predication of the theistic personalists--God and nature are of the same order of being--except in reverse. This is why St. Thomas is the bomb. :-)
Before I reply to Beckwith, let us make sure we understand how the Spinozistic conception of God differs from, while partially overlapping with, the traditional conception we find in Augustine, Aquinas, et al. Steven Nadler in SEP writes,
According to the traditional Judeo-Christian conception of divinity, God is a transcendent creator, a being who causes a world distinct from himself to come into being by creating it out of nothing. God produces that world by a spontaneous act of free will, and could just as easily have not created anything outside himself. By contrast, Spinoza's God is the cause of all things because all things follow causally and necessarily from the divine nature. Or, as he puts it, from God's infinite power or nature “all things have necessarily flowed, or always followed, by the same necessity and in the same way as from the nature of a triangle it follows, from eternity and to eternity, that its three angles are equal to two right angles” (Ip17s1). The existence of the world is, thus, mathematically necessary. It is impossible that God should exist but not the world. This does not mean that God does not cause the world to come into being freely, since nothing outside of God constrains him to bring it into existence. But Spinoza does deny that God creates the world by some arbitrary and undetermined act of free will. God could not have done otherwise. There are no possible alternatives to the actual world, and absolutely no contingency or spontaneity within that world. Everything is absolutely and necessarily determined.
The two conceptions overlap in that for both the traditionalist and the Spinozist, there is exactly one God who is the necessarily existent, uncreated, and the ground of the existence of everything distinct from itself. But there are important differences. For Spinoza, God is immanent, not transcendent; not libertarianly free; not capable of existing on his own apart from nature. There are other differences as well.
Beckwith's response implies that the orthodox Thomist and the orthodox Spinozist refer to the same God, but that the Spinozist harbors some false beliefs about God, among them, that God is not a libertarianly free agent who could have created some other world or no world at all. On the traditional conception, God does things for reasons or purposes while for Spinoza, "All talk of God's purposes, intentions, goals, preferences or aims is just an anthropomorphizing fiction." (Nadler)
As I see it, there is no one God that both the Thomist and the Spinozist succeed in referring to. If the God of Aquinas exists, then the God of Spinoza does not exist. And contrapositively: if the God of Spinoza does exist, then the God of Aquinas does not. This strikes me as evident even if we don't bring in the point that for Aquinas God is ipsum esse subsistens. If we do bring it in it is even more evident.
From my point of view, Beckwith makes the following mistake. He apparently thinks that the overlap of the Thomistic and the Spinozistic God concepts suffices to show that in reality there is exactly one God to which both Thomists and Spinozists refer. It does not.
Suppose the common concept is instantiated. Then it is instantiated by something that exists. But existence entails completeness:
EX --> COMP: Necessarily, for any existent x, and for any non-intentional property P, either x instantiates P or x instantiates the complement of P.
What the principle states is that every real item, everything that exists, satisfies the property version of the Law of Excluded Middle. Nothing in reality is incomplete. So if the common God concept is instantiated, then it is instantiated by something that is either libertarianly free or not libertarianly free. A concept of God can abstract from this alternative. But God in reality must be one or the other. Since successful reference is reference to what exists, Thomist and Spinozist cannot be referring to one and the same God.
Objection. "Why not? if Thomism is true, they are both referring to the Thomist God, and if Spinozism is true, they are both referring to the Spinozist God."
Reply. There are two conditions on successful reference. First, the referent must exist. Second, the referent must satisfy the understanding of the one who is referring. As I said in an earlier post, successful reference requires the cooperation of mind and world. The second condition is not satisfied for the Spinozist if Thomism is true. The Spinozist intends to refer to a being that is not libertarianly free. His reference cannot be called successful if, willy-nilly, he happens to get hold of the Thomist God.
Shooting analogy. A sniper has a Muslim man in his sights, a man whom the sniper believes is a jihadi he must kill. Next to the man is a Muslim woman whom the sniper believes is not a jihadi and whom he endeavors not to harm. Unbeknownst to the sniper, it is the woman who is the jihadi and not the man. The sniper, aiming at the man, gets off his shot, but misses him while hitting the woman and killing her. Question: has the sniper made a successful shot? No doubt he hit and destroyed a jihadi. That's the good news. The bad news is that he missed the target he was aiming at. He failed to hit the target he intended to hit.
So I say the sniper failed to get off a successful shot. He just happened to hit a jihadi. He satisfied only one of the conditions of a successful shot. You must not only hit a target; you must hit the right target. Suppose I score a bull's eye at the shooting range, but the bull's eye belongs to the target of the shooter to my right. Did I get off a successful shot? Of course not: I failed to hit what I was aiming at.
Same with successful reference: You must not only hit something; you must hit the right thing. Now what makes a thing the right thing is the intention of the one who refers. When a jihadi screams, Allahu akbar! he intends to refer to the voluntaristic, radically unitarian, God of Islam, not the triune God. If he happens to latch on to the triune God, then he has failed in his reference. He has failed just as surely as if there is no God to refer to.
Traditional Theism and Reductive Pantheism: Same God?
Suppose we define a reductive pantheist as one who identifies God with the natural world -- the space-time system and its contents -- where this identification is taken as a reduction of God to nature, and thus as a naturalization of God, as opposed to a divinization of nature. In short, for the reductive pantheist, God reduces to the physical universe. God just is the physical universe. (I take no position on whether Spinoza is a reductive pantheist; I suspect he is not, but this is a question for the Spinoza scholars.)
Now do the traditional theist and the reductive pantheist believe in, worship, and refer to the same God, except that one or the other has false beliefs about this same God? The traditional theist holds that God is not identical to the physical universe, while the reductive pantheist holds that God is identical to the physical universe. Does it make sense to say that one of them has a false belief about the same God that the other has a true belief about?
This makes no sense. To maintain that God just is the physical universe is tantamount to a denial of the existence of God. Either that, or 'God' is being used in some idiosyncratic way.
What we should say in this case is that the respective senses of of 'God' are so different that they rule out sameness of referent.
Someone who worships the physical universe is not worshiping God under a false description; he is not worshiping God at all. He is worshiping an idol.
Now Spinoza, as I read him, is not a reductive pantheist. But if you can see why the reductive pantheist does not worship the same God as the traditional theist, then perhaps you will be able to appreciate why it is reasonable to hold the same of the Spinozist.
And if I can get you to appreciate that, then perhaps I can get you to appreciate that it is scarcely obvious that Christian and Muslim worship the same God.