Worst Arguments For Christianity

[Angrboda]

Knowing from the Inside/Having a Point of View

For Nagel, there is something special about having an introspective capacity — a capacity to know one's thoughts, feelings, and sensations from the inside, as it were. One's experiences have a certain unmistakable, phenomenological character, such as the felt quality of pain or the perceived character of red. One therefore has a subjective point of view. It is the qualia or qualitative character of experiences, sensations, feelings, and so forth, to which we have introspective access, and it is this that, in Nagel's view, is not reducible to neural states. These mental states resist reduction because introspective access to them has an essentially different character, yielding essentially different information, than does external access via neuroscience. The argument does exert a powerful attraction, but as stated it is still teasingly vague. In order to see exactly how it works, it is necessary to set out a more precise version.

(A)
(1) The qualia of my sensations are knowable to me by introspection.
(2) The properties of my brain states are not knowable to me by introspection.
Therefore:
(3) The qualia of my sensations =/= the properties of my brain states.

A second argument, complementary to the first, seems also in play:

(B)
(1) The properties of my brain states are knowable by the various external senses.
(2) The qualia of my sensations are not knowable by the various external senses.
Therefore:
(3) The qualia of my sensations =/= the properties of my brain states.

The general form of the argument seems to be this:

(1) a is F
(2) b is not F
Therefore:
(3) a =/= b

Leibniz's law says that a = b if and only if a and b have every property in common. So if a = b, then if a is red, b is red, if a weighs ten pounds, then b weighs ten pounds, and so forth. If a is red and b is not, then a =/= b. Assuming their premises are true, arguments (A) and (B) appear to establish the nonidentity of brain states and mental states. But are their premises true?

Let us begin with argument (A). There is no quarrel with the first premise (the qualia of my sensations are known-to-me-by-introspection), especially since qualia are defined as those sensory qualities known by introspection, and in any case I have no wish to deny introspective awareness of sensations. In contrast, the second premise (the properties of my brain states are not known-to-me-by-introspection) looks decidedly troublesome. Its first problem is that it begs the very question at issue-that is, the question of whether or not mental states are identical to brain states. This is easy to see when we ask what the justification is for thinking that premise true.

The point is this: if in fact mental states are identical to brain states, then when I introspect a mental state, I do introspect the brain state with which it is identical. Needless to say, I may not describe my mental state as a brain state, but whether I do depends on what information I have about the brain, not upon whether the mental state really is identical to some brain state. The identity can be a fact about the world independently of my knowledge that it is a fact about the world. Similarly, when Jones swallows an aspirin, he thereby swallows acetylsalicylic acid, whether or not he thinks of himself thus; when Oedipus kissed Jocasta, he kissed his mother, whether or not he thought of himself thus. In short, identities may obtain even when we have not discovered that they do. The problem with the second premise is that the only justification for denying that introspective awareness of sensations could be introspective awareness of brain states derives from the assumption that mental states are not identical with brain states. And that is precisely what the argument is supposed to prove. Hence the charge of begging the question. (Although I have used (A) as an illustration, the same kind of criticism applies equally to (B).)

Other problems with these arguments are more subtle. One difficulty is best brought out by constructing an argument analogous to (A) or (B) with respect to the character of the properties under discussion and comparing the arguments for adequacy. Consider the following arguments:

(C)
(1) Smith believes Hitler to be a mass murderer.
(2) Smith does not believe Adolf Schicklgruber to be a mass murderer.
Therefore:
(3) Adolf Schicklgruber =/= Adolf Hitler.

As it happens, however, Adolf Schicklgruber = Adolf Hitler, so the argument cannot be right.

Or consider another instance of the general argument form where the property taking the place of F is a complex property concerning what John believes or knows:

(D)
(1) Aspirin is known by John to be a pain reliever.
(2) Acetylsalicylic acid is not known by John to be a pain reliever.
Therefore:
(3) Aspirin =/= acetylsalicylic acid.

And one final example more closely analogous to the arguments at issue:

(E)
(1) Temperature is directly apprehendable by me as a feature of material objects.
(2) Mean molecular kinetic energy is not directly apprehendable by me as a feature of material objects.
Therefore:
(3) Temperature =/= mean molecular kinetic energy.

These arguments fail because being-recognized-as-a-something or being-believed-to-be-a-something is not a genuine feature of the object itself, but rather is a feature of the object as apprehended under some description or other or as thought about in some manner. Having a certain mass is a property of the object, but being-thought-by-Smith-to-have-a-certain-mass is not a genuine property of the object. Such queer properties are sometimes called "intentional properties" to reflect their thought-mediated dependency. Notice that in (B) the property is being-knowable-by-the-various-external-senses, and in (A) the property is being-known-by-me-by-introspection. Both are sterling examples of thought-dependent properties.

Now the arguments (C) through (E) are fallacious because they treat intentional properties as though they were genuine properties of the objects, and a mistake of this type is called the intentional fallacy. It is evident that the arguments designed to demonstrate the nonidentity of qualia and brain states are analogous to arguments (C) through (E). Consequently, they are equally fallacious, and the nonidentity of mental states and brain states cannot be considered established by arguments such as (A) and (B).

The last difficulty with the arguments is better seen in a slightly different and more compelling version of the argument for the nonidentity of mental states and brain states, which I present and discuss below. [Discussion of Mary the Neuroscientist omitted]

- Neurophilosophy, Patricia Churchland