blog.kennypearce.net

"Common Sense," "Pre-Theoretical Intuitions," and Philosophy

I am presently reading Peter van Inwagen's Material Beings (I'm not sure if it's going to actually help with my very strange philosophy of religion term paper wherein I argue that idealism is compatible with a belief in the bodily resurrection of the dead, or if I'm just procrastinating). In section 10, after denying that there are, in metaphysical rigor, any artifacts (i.e. inanimate macrophysical objects, such as chairs), van Inwagen makes the following remark:

Does my position not fly in the face of common sense? I do not think so. This is not because I think that my position is in accord with "common sense," but rather because I do not think that there is any such thing as the body of doctrine the philosophers call common sense. There is common sense: Common sense tells us to taste our food before we salt it and to cut the cards. It does not tell us there are chairs. (p. 103)

Van Inwagen implies that common sense does dictate that when people say such things as "there are two very valuable chairs in the next room" they may, under the correct circumstances, say what is true, despite the fact that (according to his theory) there are (in metaphysical rigor) no chairs (p. 100). According to van Inwagen, the sentence "there are two very valuable chairs in the next room" is like the sentence "It was cooler in the garden after the sun had moved behind the elms" (p. 101). It is "common sense" that both sentences sometimes express truths, but the former is not inconsistent with van Inwagen's theory, and the latter is not inconsistent with Copernican astronomy. As it turns out, we simply don't have any "common sense" about Ptolemaic vs. Copernican astronomy, or about theories of mereology.
Berkeley, unsurprisingly, had to deal with the same sort of objection. Curiously enough, however, Berkeley attempts to turn the objection around against his opponent:

I am content ... to appeal to the common sense of the world for the truth of my notion. Ask the gardener, why he thinks yon cherry-tree exists in the garden, and he shall tell you, because he sees and feels it; in short, because he perceives it by his senses. Ask him why he thinks an orange-tree not to be there, and he shall tell you, because he does not perceive it. What he perceives by sense, that he terms a real being, and saith it is, or exists; but that which is not perceivable, the same, he saith, hath no being. (Three Dialogues Between Hylas and Philonous, 3.234)

The idea is that people have common sense about the existence of trees: they can touch them, smell them, sit under them, eat their fruit - they exist. But people don't have common sense about "matter," whether matter is defined in the Lockean sense as "a material substratum; a substance capable of supporting accidents" or in the physics sense as "that which has mass/inertia and takes up space." And they certainly don't have common sense about whether the matter described by physics is ontologically fundamental, or mind-dependent, or epiphenomenal, or what. The commonality between van Inwagen and Berkeley (though van Inwagen is by no means an idealist - in fact, though he believes in God and angels and so forth, and these beings are clearly not embodied, he's a physicalist about human persons) is that people have common sense about the possibility of seeing chairs, and sitting in them, and so forth, but they don't have common sense about the existence of chairs in any metaphysically interesting sense. Berkeley argues, of course, that common sense is phenomenalist about material objects, and this comes out in attempts to use Moore's "two hands" argument against Berkeley, or in Samuel Johnson's famous "refutation," which consisted of kicking a rock. In both cases phenomenalism is implicitly assumed: my hands are there because I can see them, the rock is there because I can kick it.

Our "common sense" ideas are sometimes called "pre-theoretical intuitions" and the use is not limited to material objects. In the context of a debate on whether laws govern, Susan Schneider presents a reasoning principle she calls (C): "Ceteris paribus, choose the philosophical theory of F that best accomodates our (relevant) pretheoretic intuitions about F." ("What is the Significance of the Inuition that Laws of Nature Govern?", forthcoming in the Australasian Journal of Philosophy) This principle, she thinks, militates against "Humean supervenience" (regularity) accounts of lawhood. I actually think that this principle is probably correct. However, I think it is almost entirely irrelevant. We almost never have intuitions about matters of philosophical interest which are both relevant and pretheoretic. For instance, in the lawhood debate, our inuitions come from a long tradition of science and philosophy. In the debate about material beings, Berkeley thinks that our 'intuitions' come from indoctrination with Aristotelian metaphysics, from which even the moderns have not escaped. People who have never studied philosophy or science don't have intuitions about this sort of thing.

Now, I do think there is one intuition that is relevant to the lawhood debate, and I think it is the intuition that those who hold the governing conception of laws are really getting at. This is what I was refering to when I was making inflammatory remarks about Armstrong-laws (I didn't intend them to be too terribly inflammatory, but commenter "Marc" was apparently rather upset, prompting me to clarify my actual position). It is, in fact, the intuition behind teleological arguments for the existence of God: to state it at its most general, this intuition says "where there is a rational order, there must be a rational ordering principle." This needn't be the traditional God, but may instead be something like (as I said in the previous post) the Heraclitean logos. This intuition is relevant while the others are not because it is actually within the realm of common sense: we distinguish between objects formed by random undirected processes and objects formed by processes with a rational ordering principle behind them all the time. Common sense is well adapted only for dealing with things we ordinarily encounter in everday life. Similarly, we have pretheoretical intuitions only about things we have reason to "intuit" about before we begin theorizing. Thus common sense and intuition are relevant to philosophy only rarely.

For the record, in those cases where it is relevant, I think that the reason it works is that we often go through rational deductive processes of which we are not even conscious. That is, we draw valid inferences, but a philosopher is at great pains to formalize and bring to light those inferences. This, I think, is the case with these "teleological" intuitions.

Persons as Events

Over the semester break, I took some time to look at Peter van Inwagen's paper "Materialism and the Psychological-Continuity Account of Personal Identity" (Philosophical Perspectives 11 (1997): 305-319) and, as I realized that I don't have a good candidate for submission to Monday's Philosopher's Carnival, I thought this would be a good time to write down some thoughts that I had in connection with this paper and (very) broadly Lockean "psychological continuity" accounts of personal identity in general.

The aim of van Inwagen's paper is to show that these kind of psychological continuity accounts require the existence of immaterial substances, and so are incompatible materialism. He takes aim at what I see as the primary flaw of contemporary analytic philosophy: the attempt to isolate from one another philosophical issues that are in fact inextricably connected. In this case, this is primarily the attempt separate personal identity from the rest of ontology, which, I agree with van Inwagen, is not a good idea, and is probably nearly impossible.

However, I do think there is a version of the psychological continuity account that IS very nearly ontologically agnostic, and is at least agnostic as to the existence of material and immaterial substance, which is precisely what Locke claims about his theory. I will not spend time here making any arguments that the theory I'm presenting is Locke's (although I think it probably is), but I do want to show that there is a broadly Lockean account here that avoids van Inwagen's argument. This account makes a highly unusual assertion: according to it, persons are not in fact substances but events.

According to any psychological continuity account of personal identity, persons remain the same over time because their mental states bear a certain relationship to one another. In Locke's case, memory is emphasized, but I do not think this is necessary. It would be just as easy to say that a person A existing at time T1 is the same as a person B existing at a later time T2 if and only if B's mental state can be explained by a series of previous mental states leading back to A. This is of course not a rigorous formulation, and cannot handle all objections, but you get the idea. At any rate, the mental state of person B is connected to the mental state of person A in some relevant way, which leads us to assert that they are the same person.

Now, Locke is committed to a theory of what is called relative identity (see van Inwagen's brilliant paper "And Yet There are Not Three Gods, But One" in the collection Philosophy and the Christian Faith, ed. Thomas V. Morris for a rigorous account of relative identity). Relative identity is the claim that in at least some cases we cannot answer the question of whether A is the same as B without first asking, "The same what?" In particular, Locke thinks that although one being might be simultaneously a material object, a human, and a person, the question of whether it is the same material object, the same human, and the same person may in some conceivable cases have different answers. In the everyday case, it will not be the same material object over time because of the constant intake of food, elimination of waste, sloughing of dead skin cells, etc., that cause it not to be made up of the same matter. It will be the same human over time because it has continuity of organization as a living organism. It will be the same person over time because is has psychological continuity in the form of memory. What is curious about Locke's account is he envisions the case where two entities are compared and turn out to be the same person while NOT being the same substance. This would occur, for instance, if two souls (assuming, for the moment, that souls exist) were to swap memories.

The core of the strangeness of this account comes, I believe, from the fact that we are comparing things that we think of as being substances (persons) based on events that occur within them (mental states). We wouldn't normally do this. Now, perhaps we want to say that the mental state is the collection of properties of the person, and the person's having those properties is an event. This is where van Inwagen's attack comes in, since the materialist (allegedly) cannot say that the person is distinct from his body. Now, I'm not familiar with the particular accounts of materialism van Inwagen attacks here, but it seems to me that the materialist is only committed to saying that the person does not exist as a substance independent of the body. Van Inwagen presents a further attack by pointing out that if the person is identical with the physical body, then whatever is predicated of the person can be predicated of the body. However, if it is possible for persons to switch bodies, this will lead to the breakdown of the transitivity of the (absolute) equality relation. By way of illustration (an illustration different than van Inwagen's) let NBx (where x is a numeric subscript) be the new body at time x, and Px be the person at time x. The transfer occurs at time 2. We have:

NB1 != P1
NB3 = P3
P3 = P1
NB3 = NB1

Thus the equality relation would transitivity. There are some things that can be predicated of the body that cannot be predicated of the person, therefore they are ipso facto not equal, and the person either does not exist or is distinct from the body.

I believe that both of these objections can be escaped, on a reasonable definition of materialism. That is, it may be reasonable to define materialism as the view that only material substances exist, but it is also reasonable to define it as the view that there are no substances other than material ones. This difference is significant, because many ontologies posit that substances are not all that are "real" - events are also real in an important sense. If persons are viewed as complex events consisting of series of psychological states, then they can exist without being identical with any physical objects; they simply need physical objects to "inhere" in. We would say, then, that each mental state is a "time-slice" of a person, a simple event consisting in (according to the materialist) some brain having certain properties. The person is a complex event consisting of a collection of such simple events which are related to each other in some relevant way, such that we say that any one mental event in the collection is "continuous" with all the others. These events need not inhere in the same material object. This could be defined rigorously by making explicit what types of properties are relevant to psychological continuity.

For the record, I do believe this theory of persons and events, although I am not a materialist. I think that it is the best account of what it is we mean by the word person; for the mental states that we speak of in terms of personhood are clearly events and, as Locke's arguments show, what substance they happen in doesn't seem to be relevant. This possibility is completely absent from van Inwagen's paper, and I'm really not entirely sure why.