Monday, June 21, 2021

Self-locating beliefs in the Trinity

Here is a difficulty for the doctrine of the Trinity that I don’t remember coming across before:

  1. The Father and the Son have the numerically same divine mind.

  2. If x and y have the numerically same divine mind, then x and y have the same divine beliefs.

  3. The Father has an “I am the Father” divine belief.

  4. So, the Son has an “I am the Father” divine belief. (1–3)

  5. An “I am the Father” divine belief in the Son would be false.

  6. There are no false divine beliefs.

  7. So, the Son has no “I am the Father” divine belief. (5–6)

  8. Contradiction!

Here, premise (1) follows from the heuristic that what there are two of in Christ, there is one of in the Trinity: there are two minds in Christ, so one mind in the Trinity. Non-heuristically, if there are two minds in Christ—the human and the divine mind—the mind must be a function of the nature, and as there is one divine nature in the Trinity, there is one mind in the Trinity.

There is a quick way out of the paradox: Restrict premise (2) to propositional beliefs rather than de se or self-locating beliefs. The belief that would be expressed in English by “I am the Father” is a de se or self-locating belief. There are corresponding propositional beliefs, such as the belief that the Father is the Father and the Son is the Son, but these are unproblematically had in common by the Father, the Son and the Holy Spirit.

However, while this quick way gets one out of the argument, it nonetheless leaves raises the difficult question of how it is the Father knows de se that he is the Father and the Son knows de se that he is not the Father, while yet there is one mind.

The solution had better be in terms of the relations between the divine persons, for there is no difference between the persons of the Trinity except the relational. I am reminded here of Thomas’s discussion of creation and the Trinity:

And therefore to create belongs to God according to His being, that is, His essence, which is common to the three Persons. Hence to create is not proper to any one Person, but is common to the whole Trinity.

Nevertheless the divine Persons, according to the nature of their procession, have a causality respecting the creation of things. For as was said above, when treating of the knowledge and will of God, God is the cause of things by His intellect and will, just as the craftsman is cause of the things made by his craft. Now the craftsman works through the word conceived in his mind, and through the love of his will regarding some object. Hence also God the Father made the creature through His Word, which is His Son; and through His Love, which is the Holy Ghost. And so the processions of the Persons are the type of the productions of creatures inasmuch as they include the essential attributes, knowledge and will.

Thus, each divine person is fully the Creator, but is fully the Creator in a way that takes into account the relationship that defines the person in the Trinity: the Father creates in a Fatherly way, the Son as the Logos through which creation is done, and the Spirit as the Love in which creation is inspired. What makes it be the case that the Father creates in a Fatherly way is just that the Father creates and he stands in the relations that constitute him as Father; what makes it be the case that the Son creates in a Filial way is just that the Son creates and he stands in the relations that constitute him as Son; and similarly for the Holy Spirit.

We might thus imagine the following story. There is a state F of the divine mind such that the Father’s Fatherly instantiation of F constitutes F into a belief that he (de se) is the Father. The Son instantiates the numerically same state F in a Filial way. But while a Fatherly instantiation of F is correctly described in English as constituting an “I am the Father” belief, a Filial instantiation of F is not aptly so described. Perhaps, a Filial instantiation of F is aptly described as a believing of “I am the Son of the one who is the Father.” Thus, the de se beliefs of the persons of the Trinity are constituted by mental states common to the Trinity and the relations constituting the persons.


El Filósofo said...

Dr. Pruss, what is your opinion that the Trinity is incompatible with divine Simplicity?

Alexander R Pruss said...

There is no incompatibility on Aquinas' take on both doctrines.

Alexander R Pruss said...

Two notes on my post

1. Tim Pawl tells me that he heard the puzzle from Mike Rea.

2. It's worth noting that even in ordinary humans, there is a slightly similar puzzle. Consider the "I am a human being" belief that I have, call it H. This belief is found in me AND in my mind. This suggests this oddity: There are two things here that have H in them, one of them is me and the other is my mind. And paradoxically H is true when found in me and false when found in my mind, since my mind is not a human being. But this paradox can be resolved as follows: by its relation to me, H constitutes me as believing that I am a human being; but by its relation to my mind, H does not constitute my mind as believing anything at all, since minds don't believe.

The case of God is somewhat similar: the same state or feature F constitutes the Father as believing one thing and does not constitute the Son as believing the same thing.

swaggerswaggmann said...

Another way is that all states are in superposition, every member know all the states, but only use the ones he see fitting, based upon his previous states.

The superposition guarantee the mind is the same but with different outcomes depending upon the way it is used.

Michael Gonzalez said...

Just a couple of notes (without going into a full-blown argument against the Trinity doctrine):

1) I have thought of this problem many times in discussions with Trinitarians, and I find that it isn't just beliefs, but also desires, intentions, and even powers which differ among the "divine persons". The Father does not desire or intend to obey anyone; the Son does. The Son does not have the power to produce a divine person; the Father (if I understand the doctrine correctly) does.

2) Is there not an indebtedness to the Father, of which the Son would be aware and for which he would be grateful? Jesus, while on Earth, said "I live because of the Father". Of course, you will say that that was true of his human nature, but is it not also true of his putative divine nature?

I'm reminded of how Richard Swinburne has described the situation: He says that the arguments of natural theology point to the existence of a single person, namely the Father. The Father, in turn, because He sees that it would be good, causes the Son (a similar reason to why He causes the physical world to exist: He sees that it would be good and has no contrary beliefs). So, shouldn't the Son be in a mental state similar to ours with respect to the Father and our own existence?

3) Leaving aside all the Trinity stuff, what on Earth does it mean when you say that the belief "I am a human being" is "found in me AND in my mind"?? I'm not being sarcastic; I genuinely have no idea what that distinction is supposed to mean. If the phrase "belief H is found in/had by my mind" has any meaning, it is surely the very same as saying "belief H is found in/had by me", which I very much hope is just a fanciful and metaphorical way of saying "I believe H"....

Alexander R Pruss said...


Regarding 1 and 2, you are quite right. The point comes up for other mental states. Divine simplicity requires a content-externalism about divine mental states (because the contents of some of God's mental states will be different in different possible worlds, but nothing intrinsic to a simple being can be different in different possible worlds), and Trinitarianism requires a kind of content-relationalism about divine mental states, on which the content of a mental state of a divine person depends on the mental state as such and the person's relation to the other persons of the Trinity. This to beliefs, desires, etc.

Regarding 3, I know you don't believe in minds. But I am inclined to. I also believe in accidents, and thoughts are accidents. Suppose for simplicity (and contrary to fact) that the brain is the mind. Then when I believe "I am a human being", there is some accident H of my brain in virtue of which it is the case that I believe I am a human being. This accident H is a belief and it is in my brain. H is my belief. But it is not my brain's belief, because brains don't believe things.

Michael Gonzalez said...


Regarding the Trinity: I completely defer to you on these carefully worked out conceptual models that you mentioned, as I don't know much at all about them. Putting aside what I take the Bible to teach, I do have one question: Given the content-externalism and content-relationalism that you mention, what exactly does one say about one divine person regarding another as his God and as the source of his existence, without which he would not exist, while that other one has no such dependency or indebtedness? Not having the background that you have, I just see "God" and "not-God" in that situation.

Regarding minds: I see a knot within a knot here, and I would love to know your response to this. Here are a couple of questions to draw it out (and note that I may be totally mistaken, as usual!)

1) How do we get from "there is some accident, H, of my brain in virtue of which it is the case that I believe I am a human being" to "H is a belief"? H is a brain state without which I would not hold the belief, but I don't see how that makes H itself a belief.... Let alone "H is a belief with a location" (do beliefs have locations?). Let alone "H is a belief located in my brain" (why must the belief's location be the same as the accident in virtue of which the belief is held by me?).

I just feel like there are several hidden premises here.

2) If brains don't believe things, then does the brain "having a belief" mean something akin to a filing cabinet "having information"? If I need to pull out the file and read it in order to know X, does it follow that the filing cabinet already knew X or that it has any knowledge at all (in the sense in which I have knowledge)?

Alexander R Pruss said...

Regarding the Father being Christ's God, that can be read in two ways:
- The Father is the God of Christ's human nature
- God is God's God.

Moreover, the Father is the eternal non-causal source of the Son's existence, and the Father and the Son (though the Eastern Orthodox dispute the "and the Son") are the eternal non-causal source of the Holy Spirit's existence. These are the "processions".

Regarding beliefs, the brain having a belief would be rather like the filing cabinet having information: there is information in the filing cabinet, and there is (assuming materialism) a belief in the brain. But the filing cabinet is not informed by the information, and the brain doesn't believe the belief.