Of Plantinga's three anti-naturalist arguments in this chapter, I found his argument against materialism the most persuasive (for me). Perhaps it is because I very much strongly share the intuition he is expressing. Consider the works of philosophers of mind like Colin McGinn (on cognitive closure), Joseph Levine (explanatory gap), Ned Block (the China argument), and John Searle (the Chinese room argument). It seems to me that the intuition that Plantinga is pointing us to is what is driving many of the arguments of these philosophers of mind, and I find that this intuition compels me against materialism.
The crux of Plantinga's argument against materialism, I think, is in this passage (where, in talking about contents, he's talking about belief-contents):
The fact is, we can't see how it could have a content. It's not that we see or know this is perfectly possible, but we just don't know how it's done. When light strikes photo-receptor cells in the retina, there is a complex cascade of electrical activity, resulting in an electrical signal to the brain. I have no idea how all that works; but of course I know it happens all the time. But the case under consideration is different. Here it's not merely that I don't know how physical interaction among neurons brings it about that an assemblage of neurons has content and is a belief. No, in this case, we can't see how such an event could have content--that is, it seems upon reflection that it could not have content. It's a little like trying to understand what it would be for the number seven, e.g., to weigh five pounds (or for an elephant to be a proposition). We can't see how that could happen; more exactly, we can see that it couldn't happen. A number just isn't the sort of thing that can have weight; there is no way in which that number or any other number could weigh anything at all. (The same goes for elephants and propositions.) Similarly, we can see, I think, that physical activity among neurons can't generate content. These neurons are clicking away, sending electrical impulses hither and yon. But what has this to do with content? How is content or aboutness supposed to arise from this neuronal activity? How can such a thing be a belief? You might as well say that thought arises from the activity of the wind or the waves. But then no neuronal event can as such have a content, can be about something, in the way in which my belief that the number seven is prime is about the number seven, or my belief that the oak tree in my backyard is without leaves is about that oak tree. (p. 54)
Here's one way I formulate an argument against materialism in my head. It is not exactly Plantinga's argument, but it is suggested by the quote:
1) I can reasonably believe that it is impossible that a number has weight based on "seeing" that it is true.
2) I can "see" that it is impossible that an interaction of physical objects have content or be a belief, and this "seeing" is relevantly analogous to the "seeing" in premise (1).
3) I can reasonably believe that it is impossible that an interaction of physical objects have content or be a belief
(This isn't deductively valid, but an argument from analogy. If we wanted a deductively valid argument, we could add a premise about how arguing analogically gives likelihood of truth and then conclude that (3) is likely to be true or something like that, but I thought that'd complicate things. I hope I didn't make any embarrassing moves.)
How are the two "seeings" relevantly analogous? Well, I think that they are phenomenally the same. They are both motivated similarly: just as it seems that numbers aren't the sorts of things that could have weight, it seems that physical objects (and their arrangements and their interactions) aren't the sorts of things that could have thoughts or beliefs (or be thoughts or beliefs). Clayton's suggested (in a comment in the last post) that the latter seeing would take "special epistemic powers", but I don't see how the powers at work here are any different from the powers at work when seeing that numbers can't have weight. (Furthermore, Clayton, I agree that I can't see how molecules could be arranged so as to have the properties of a computer, but I don't think I have a "seeing" that it is impossible; the exemplifying of computer properties from interactions of material objects seem perfectly possible. Your computer illustration strikes as me as similar to Plantinga's illustration of light striking the retina in the above quote.)
Here's how the intuitions are disanalogous, and this could block the jump from (1) and (2) to (3). There are no arguments out there that numbers could have weight, but there are arguments by smart people that material objects can think. This would make me hesitant to conclude (3). However, Plantinga thinks that materialists simply avoid this problem (what he calls Leibniz's problem, p. 61), and he gives an example with Dretske's theory. I'm inclined to agree with Plantinga's assessment, but only very hesitantly so, since I'm no philosopher of mind and I'm not aware of the arguments out there (nor am I very aware of the contemporary literature). It has seemed to me from what I have read, however, that materialists do tend to make a quick jump from what Plantinga calls "indicator content" or representations to belief. The jumps I have read have struck me as tenuous (or at least they strike me as more tenuous now that Plantinga has pointed them out). Anyway, this is how I see the argument and this is why I am persuaded by it.
Hey Andrew,
I think I'm sceptical of the claim that the intuition driving some of the philosophers you mention is the same as the one driving Plantinga. On its face, it seems that the intuition behind those who think that there is this explanatory gap is just that we cannot see how the mental and material are related, not that we can see that they are unrelated.
Let's look at the number/weight; material object/thought analogy just a bit.
(1) It is part of our concept of number that it is an abstract object.
(2) It is part of our concept of abstract object that it lacks the sort of spatial properties it must have to have mass, weight, etc...
(C) So, we know apriori that numbers don't have weight.
I don't see how a parallel line of reasoning would work for the case of material object/thought. I cannot see that my grasp of the essence of material object excludes cognition, consciousness, etc... I cannot see that my grasp of belief, thought, or experience excludes that these are modes or attributes of a material substance.
Maybe I'm just more Cartesian in my thinking and you and Plantinga are more Leibnizian, but it seems to me that the following are true:
(1') It is part of our concept of belief that beliefs belong to substances.
(2') It is no part of our concept of belief that they belong to substances that are themselves immaterial.
(3') While the power to think is not part of the essence of body, there is nothing to the concept of body that excludes the possibility of thought.
I don't know which of these (1')-(3') you can just 'see' is false, but if you cannot 'see' that at least one is false, I'd think that the proper stance to take towards the possibility of a material thinking thing is agnosticism rather than denial. No argument paralleling the argument for the impossibility of heavy numbers springs to mind and if no such argument could be given I'd be unimpressed with the claim that one could just 'see' that numbers could not have weight. I think in light of what seem to be significant differences between the two cases, we should want more in a refutation of materialism about the mental.
When parts of the brain are damaged, certain mental properties can go out of existence. When parts of the brain are stimulated, certain mental properties come into existence. We have a good reason to think there is a material thing, the brain, and mental properties, our thoughts, that are causally related. So, it seems to me, we have a very good reason to think that a material thing can generate content. Moreover, we know how to do it. Stimulate your brain in certain places and you will feel pain. There is nothing, then, special about the material giving rise to the mental. Perhaps it is the "aboutness" of content that Plantinga thinks a material object, a brain, could not cause to exist. But we have a nice story there too. When the brain is put into certain states, by objects external to it, in the right way, the mental properties the brain gives rise to, when so related, are about the external object in question. That seems clearly possible. That's enough, as far as I can tell, to show that it ought not seem impossible for there to be content. And then it's an open question just which story is the best story about these causal relations.
Clayton,
Thanks for the comments, and I think that they advance the discussion. I hope to get back to you shortly after I think a bit more about it. I might disagree with your (2') and (3').
Christian,
The "generating" content that Plantinga's getting at is not that physical states can cause belief with contents to exist. A interactionist dualist agrees with that. I was a bit surprised that you understood the statements about generating content that way (given everything else Plantinga says). He's talking about the interaction of physical objects being a belief that has content. And it seems to me that that's impossible.
On your second part, it seemed to me that you weren't taking into account my last paragraph (and Plantinga's discussion referenced there). Or at least I'll say that it's hard to assess what you say unless you distinguish between indicator contents/representations and belief-contents. This is the stuff discussed around p. 61.
I'm a bit skeptical of the claim that anyone can just 'see' that NO possible arrangement of matter, no matter HOW constituted, hooked up to the environment, etc. could EVER have any content. For one thing, I'm not sure we know enough about matter or the physical itself to be able to tell this. But for another, such intuitions generally get the most going for them when we look at, say, an isolated atom. We ask ourselves whether THAT could have content. No, it doesn't seem like it could - what would determine such content? Then we think, how could throwing a whole lot of those together add up to any content if none of them have it in the first place? (I'm not sure everyone thinks this, but many do) But I think Peter Carruthers has had some interesting things to say about this - our intuitions, which many hold strongly, start to melt, fade away, or even sometimes positively take an about-face change when we start getting material entities responding differentially to their environment. And once we keep making those things more and more complex, it can get harder and harder to not have the intuition that SOMETHING in there is representing what it is responding to.
Maybe one source of the intuition that the material cannot have content is the Searlian view that mentality and content presuppose consciousness. And then the property dualist intuitions enshrined in the explanatory gap, etc. kick in and we think that this cannot be REALLY REAL content that this "intelligent" material being has.
In any case, from what I've read on Plantinga on this, he seems to just appeal to this brute intuition without really offering much in the way of good objections to the adequacy of the various theories of content that are out there. It seems to me that if he's going to dismiss such theories, he needs to actually deal with what they get right or wrong about content, not whether they meet some particular metaphysical intuition he might have. Unlike the case of numbers having weight, these theories are actually doing work and explaining things - they are offering things which are to take on the theoretical role that content is supposed to provide. And if one of them succeeds in this(which, by the way, I'm skeptical of) then I'm not sure Plantinga's intuition really counts for much. Of course, I could be missing something Plantinga's written somewhere, so this could be off-base.
Oh, and as for "materialists do tend to make a quick jump from what Plantinga calls "indicator content" or representations to belief", that may sometimes seem to be true, but that's because the theory of content in phil mind is NOT supposed to be, usually, a theory of propositional attitudes. Materialists will usually have a different theory for that (functionalism or some related variety - most people don't realize the wide array of options available here in the phil mind/cog sci borderlands), with the theory of content providing, of course, the content of the states.
Hello Ian,
Since Plantinga's focusing on belief-content, the theories of content simpliciter aren't really relevant, right? Or those theories are only relevant insofar as they get us belief? That's the only stuff that should matter for this discussion, I think, since that's what's involved in Plantinga's argument. So I couldn't see how most of what you said was relevant. And I'll say that I do have this intuition about beliefs and material objects. And I think that many others do as well. I agree that I don't have that intuition about indicator contents, but that's not what Plantinga uses in his argument.
Now Plantinga does have a nice, detailed dissection of Dretske's view of how to get from indicator content to belief (pp. 62-66, and he thinks Dretske's view is the most plausible), and he attempts to show (and back up his earlier claim) that, in the end, Dretske ignores Leibniz's problem. I've also heard (from a friend at N. Dame) that Plantinga has a paper in the works where he responds to Fodor and Millikan (whom he only briefly discusses in the book). However, after reading his response to Dretske, the general strategy he uses makes me optimistic that he will be able to respond to Fodor and Millikan similarly.
So I think you're right that more needs to be said than what you took Plantinga to be saying, but more has been said and more (hopefully) will be said. Hmm, other than Dretske, Fodor, and Millikan, I wonder what other big players there are who have tried to come up with materialist accounts of belief? Also, you may be interested in reading the chapter (or maybe the relevant section of the book, pp. 51-66).
Hey Andrew,
I guess I'll say this about my trio:
(1') It is part of our concept of belief that beliefs belong to substances.
(2') It is no part of our concept of belief that they belong to substances that are themselves immaterial.
(3') While the power to think is not part of the essence of body, there is nothing to the concept of body that excludes the possibility of thought.
You'll grant (1'), but seem prepared to deny (2') and (3'). Let me offer a rationale for (2') and a defense of (3').
An argument for (2')
Someone can get a full grasp of the concept of belief by understanding the belief-role (i.e., the relation of that state to other states such as desire, experience, etc...).
In having a full grasp of the concept of belief at no point will represent that which plays the belief-role, desire-role, intention-role, experience-role, etc... as a state of any particular type of substance.
Thus, it is no part of the concept of belief that it is a state of an immaterial substance.
I take it that Descartes would have granted something like this. Much in the way that we do not need the concept of material body to get someone to understand what a belief is, we do not need the concept of immaterial particular to get someone to understand what a belief is. So, while it might be a metaphysical truth that only immaterial particulars can be thinkers or believers, it is not grounded in the concept of belief. Not so far as I can tell. But, you can show me how I have an incomplete grasp of the concept of belief precisely because at no point in unpacking that concept is any reference made to an immaterial substance or you can reject more broadly the functionalist idea that underwrites that argument.
A defense of (3')
As Descartes rightly noted, we could have a grasp of what it is for something to be a material body without having any understanding of how such a body could think, believe, experience, etc... However, we also know that there can be aposteriori necessities and one view that strikes me as perfectly sensible says that there are physical states that play the various roles picked out in terms of that which plays the belief-role, that which plays the experience-role, etc... If reflection on the concept of belief won't rule out this possibility, perhaps reflection on the concept of material body will.
I'm dubious. You've already granted that there are properties material bodies can have that we cannot see them to have or understand them as having in virtue of thinking about the basic material properties of the parts of these material objects. Properties can emerge from these objects that are, let's say, surprising. So, first premise:
We cannot know from knowledge of the basic material properties of parts and armchair reflection that they will have those properties. [Think of the example of the computer].
Knowing that the first premise is true, it would seem you have reason not to take the impression that you see no connection between basic material properties and emergent properties (or can conceive of the former without the latter) as reason to believe that the emergent properties do not strongly supervene on the basic material properties. [In other words, in acknowledging the first premise you have a defeater for a certain kind of modal judgment based on the intuition that you can imagine there being the basic material properties without the emergent properties].
Nothing you have said thus far indicates that the intuitions you have that would threaten the materialist claims about the mental are unlike the intuitions one might have about the possibility of, say, a profile of basic material properties in the absence of the properties that must be instantiated for there to be a functioning computer. [Just repeating the claim that I see that there's no connection as opposed to saying I don't see a connection is not itself an epistemic difference to get all worked up about because someone can _say_ the exact same thing in the computer case and it wouldn't lead us to rethink our metaphysics of laptops].
So, it seems you have a defeater for your belief that a material thing could not be the basis for the emergence of mental properties until you can articulate what it is about material bodies that exclude the instantiation of mental properties.
There is a good deal of ambiguity in what Plantinga says above. He talks about neuronal activity "having" content or "being" a belief. He wonders how content could "arise" from neuronal activity or how such activity could "be about" something. I don't want to try delineate the ways in which these things could come apart. Instead I want to focus on the idea that a material object, a brain, could not generate a belief whose content is about something. I'm interested in "generation" and not the identitification of a belief with some neurons.
You wrote: "He's talking about the interaction of physical objects being a belief that has content. And it seems to me that that's impossible."
Plantinga wrote: "Similarly, we can see, I think, that physical activity among neurons can't generate content."
If by "being" you mean "is identical to", then I agree with you. I don't see how a belief could be identical to a material object. But a naturalist need not think this. A naturalist could be a property dualist, and give an account of the generation of belief in terms of causal relations, and what a belief is in terms of a complex of concepts and mental properties, and of aboutness in terms of causal relations to particulars. And here I mean representational content, not merely indicator content. If I recall correctly (I don't have the book) Michael Tooley gave, in detail, one such account. But again, the point is simply that it is not plausible to claim that one can simply see that such an account is impossible.
Hi Andrew, I'm not sure what you mean by the difference between belief content and content simpliciter. Once you've got a theory that, say, to have content C is to have property P, all you need then is a theory which tells you WHICH things that have P are going to count as beliefs. And as far as I can tell some sort of functionalist or other similar view seems to be able to do just fine.
(Contrary to what you say, "I couldn't see how most of what you said was relevant," I'm not sure how anything I've said ISN'T relevant. Perhaps you should be a bit more specific about what exactly wasn't relevant - I put forward quite a lot considerations that could be separated.)
We have two theories here - theory of content which provides the content and theory of attitude which provides the state that has that attitude. Now, if you only think immaterial things can both have property P and count as beliefs, that, as I said, may be because you are assuming property dualism and taking it that P is tied to dualist mental properties. But that in itself only gets you to property dualism, not anything further.
As an excuse for not knowing about what else he says in this chapter, I'll just say that I've been basing my observations on that quote ALONE and its (what I would consider rather undecisive) argument - plus the similar article he published in Faith and Philosophy. That's fine if he has more, different arguments - there's plenty to complain about (I don't think any materialist theory of mental content works myself - the problems of distal content and misrepresentation are quite tricky) - I just don't think the intuition that matter cannot have content is very reliable or counts for much of anything in this debate. So his 'Leibniz argument' doesn't seem of much worth to me, even though I'd agree with his conclusion. I guess it could give one some oomph to get started in the debate, but only so one can get on to the real work.
As I said earlier about Plantinga's intuitions about matter, "I'm not sure we know enough about matter or the physical itself to be able to tell this." My concept of matter, for one, doesn't a priori exclude the mental. If you build in that restriction, sure, but then we're just talking past one another and the debate isn't really interesting anymore. Perhaps some people have been overly influenced by dualism so that their concepts of the mental and the physical have changed so as to be mutually exclusive. Or maybe there are really the property dualist intuitions that are doing the work here, as I've already suggested.
As for other, very different naturalist theories of mental representation, you can take a look at Robert Cummin's Representations, Targets, and Attitudes where he argues for a kind of isomorphism theory (which I think fails for various reasons - I've got a paper I wrote on this sitting around in my computer somewhere). There are also various variations on the theories of Dretske, Fodor, and Millikan which are meant to fix some of their problems (at the APA before last I saw a guy give a paper pushing a new dynamic-isomorphism-meets-Dretske theory - I thought his theory had a problem with generating too much content but he wasn't sure about whether that was so).
Clayton, Christian, Ian,
Thanks very much for your helpful comments, and you guys have gotten me thinking more deeply about this topic. I'm behind in matters of higher priority than the blog (teaching and dissertation proposal), but I hope to respond to your guys' points when I can (maybe in a few days). Have a good one!
nah, I probably won't get back to you guys. I might have to call "Uncle!" on this one. I have some ideas about how to respond, but they're pretty inchoate or would require a lot of defense and more time than I'm willing to give. Thanks again, though!