How does 'having an idea of something' differ from 'mental existence'?

Question

_{Source: pp 38-39, Philosophy: A Complete Introduction (2012) by Prof Sharon Kaye (MA PhD in Philosophy, U. Toronto)}

Perhaps the problem lies in Anselm's twofold conception of existence. Anselm sets out to prove that God has being-in-reality in addition to being-in-the-mind — as though being-in-reality and being-in-the-mind are two different ways for something to exist. But, on closer examination, this is a strange proposal.

When you say 'Santa Claus exists in my mind', what you really mean is 'I have an idea of Santa.' And having an idea of something doesn't necessarily mean that thing has mental existence.

Consider what happens in your brain when you think of Santa — certain neurons fire. It's not as though a little guy in a red suit literally pops into your head. It may feel like that, especially if you have a vivid imagination — it feels as though you can 'see' Santa in your mind. But a thought is actually an action — it's a tiny motion in your brain; it's not a thing at all.

If there is no such thing as 'being-in-the-mind', then Anselm's proof cannot get off the ground.

Even the 3rd paragraph's example with Santa does not aid me to comprehend the distinction asserted by the bold between having an idea of something vs mental existence.

Answer 1

I have read Kaye's text that you've just quoted several times quite carefully, and I can't see the force of her objection. She is assuming that for Anselm for us to think about God is for God himself to be existing in our heads. In other words she's saying Anselm has gone wrong by assuming a principle like the following:

(1) If I am thinking of x having some feature F, then there is an object in my mind (called O) which is F.

Kaye points out, correctly, that (1) is clearly false. When I think of a rock, my mental representation of that rock is not itself a mineral. Kaye seems to be saying that since (1) is clearly false, and Anselm's argument turns on (1), therefore, Anselm's argument doesn't get off the ground.

But I don't see why Anselm is committed to (1) at all. Anselm could deny (1) and just as easily say:

(1*) If I am thinking of x having some feature F, then I have some mental representation r that represents x's having F.

and then the argument could continue something like:

• (2) If I have a mental representation r that represents x's having F, then either r corresponds to a real object (i.e. not a mental representation) that has F or r does not correspond to a real object. (Premise)
• (3) I am thinking of God as being the greatest conceivable being, therefore I have an r that represents God as being the greatest conceivable being. (by universal instantiation of 1*)
• (4) Therefore, either (i) r corresponds to a real object, or (ii) r does not correspond to a real object. (modus ponens on 2, 3)
• (5) Suppose (ii). (Assumption for reductio)
• (6) If (ii), then I can conceive a being y who is greater than x. (Premise)
• (7) Therefore, I can conceive of a being y who is greater than x. (modus ponens 5, 6)
• (8) But I can't conceive of a being y who is greater than x. (Premise)
• (9) Therefore, not-(ii). (5-8, reductio ad absurdum)
• (10) Therefore, (my mental representation of God) r corresponds to a real object. (disjunction elimination on 4, 9)
• (11) Therefore, God exists (by 10).

That looks valid to me. Also, the premises look pretty plausible, as interpretations of Anselm. (2) doesn't turn on the specious move Kaye calls (1). (6) looks true because if x doesn't exist, then I can imagine a being y > x that is just like x except that it does exist. (That might not be true, but it's certainly something Anselm claims!) Finally (8) seems true by definition---assuming conceivability entails possibility, which Anselm does, you shouldn't be able to conceive of something greater than the greatest possible thing.

Answer 2

I have the same question like you.

I do not consider it helpful to approach Anselm's ontological "proof" by making a distinction between having an idea and mental existence.

The case of this "proof" has been settled by distinguishing

• being-in-reality and
• being-in-the-mind.

And to note that the latter does not imply the former. This fact had already been noted by a fellow monk of Anselm named Gaunilo.

But distinguishing

• being-in-the-mind = having an idea and
• mental existence

means to mix the levels and to compare things on different levels: Having an idea lives on the philosophical level of Anselms argumentation. But mental existence, as taken by Kaye, lives on the neurobiological level of firing neurons. Neurobiology is a different level than philosophy.

Possibly in the future neurobiology can explain some mechanism of argumentation, but that's not relevant for the issue of the quote.

Added. In my opinion Kaye illustrates her use of the term "mental existence" by the passage

Consider what happens in your brain when you think of Santa — certain neurons fire.

That's a description on the level of neurobiology. On the opposite, "having an idea" is a description on the level of philosophy of mind. These are two different levels of explanation.

Anyhow I must admit that I consider Kaye's statements a bit cluttered. I do not adhere to her use of the terms.