Type Identity Theory and Saul Kripke's Critique

[Aelred of Rievaulx]

Type Identity theory in the philosophy of mind may be quite a knee jerk accepted theory among many. The notion that, for example, when c-fibres within the neural network spark up then of course the subject is experiencing "pain" and of course subsequently identifying c-fibres with pain as the same thing is generally taken for granted. I would like to say, following Saul Kripke's "Naming and Necessity", that this is purely illogical and a confusion of philosophical premises.

Kripke, as is well known, is the paramount critic of type-identity theory and his argument is well known, he extends the earlier Cartesian argument for dualism in suggesting that it does not make sense to argue that a physical occurrence "c-fibres firing" is identical to a non-physical occurrence, "the qualia of pain". He does this by drawing attention again to the dramatic difference between mental states and physical states: a mental state is rationally related to another mental state however a physical state is purely causally related to another physical state.

Type identity theory would suggest that a mental state which entails pain is identical to the physical state of c-fibres firing. Given that c-fibres firing is a physical phenomenon it has a particular shape. Given the indescernability of identicals it necessitates that the mental state of pain is the shape of c-fibres firing. Given the absurdity of this supposition it entails that one of the premises must be abandoned. Abandoning type identity theory appears to be the most logical solution.

 

[GrowingSmaller]

Sound, I would go with emergence of novel properties based in c fibres etc.

 

[Aelred of Rievaulx]

Sound, I would go with emergence of novel properties based in c fibres etc.

That's an interesting notion. Bertrand Russell made a point that when philosophers of mind began to start asserting physicalism the physicists began asserting non-realism.

I would contend that no theory of mind has yet been able to offer a satisfactory enough explanation of mental states as has folk psychology, this is not to say that it never will, I'd be surprised if it ever did but I wouldn't want to stop it from attempting so. If it did attempt so I would only desire that philosophers of mind be able to scrutinise the data and its interpretation alongside the neuroscientists and psychologists. ;-)

 

[GrowingSmaller]

Folk psychology is based in phenomenology so closest to home, or closer than reductivisms. Take a candle, you can study a physics book, or look at one on the bedside table. Or the sun, an astrophysicist learns his trade in infancy so to speak, when he looks into the sky.

 

[Aelred of Rievaulx]

Folk psychology is based in phenomenology so closest to home, or closer than reductivisms. Take a candle, you can study a physics book, or look at one on the bedside table. Or the sun, an astrophysicist learns his trade in infancy so to speak, when he looks into the sky.

Well no. Folk psychology is basically the attribution of mental states to other human beings and entails the principle of charity: when I observe a person doing something I assume that they are a lover of the good and a believer in the truth. This means that when I see someone drop a cup of coffee I attribute to them the belief that a table was under their cup. We attribute reasons to people rather than causality; causality is taken as a malfunction of the mind, believing something because one wishes it to be true is a causal relation not a rational relation, believing something because it entails something else is a rational relation. This is how we approach people in our day to day and in general interactions.

Theories of mind which attempt at reducing the mind to scientific entities or redundant entities fail in providing such a clear and erudite expression of intention and reason. In terms of their scientific aptitude they are incapable of making substantive claims about what minds are and what we can expect from them. Thus, type identity theory doesn't hold much water.

Just to be clear, I haven't exactly said what does hold water - most philosophers today are non-reductive physicalists of some sort or another who accept these criticisms.

 

[Archaeopteryx]

One could say that pain is not merely c-fibres firing (i.e., the firing of c-fibres is necessary, but not sufficient, for the sensation of pain). The experience of pain depends on an entire nervous system, and not only on c-fibres. Stimulating c-fibres in a petri fish will not produce "pain."

 

[Aelred of Rievaulx]

One could say that pain is not merely c-fibres firing (i.e., the firing of c-fibres is necessary, but not sufficient, for the sensation of pain). The experience of pain depends on an entire nervous system, and not only on c-fibres. Stimulating c-fibres in a petri fish will not produce "pain."

The problem is that correlation does not entail causation and given that c fibres firing is not identical to the qualia of pain and qualia entails dramatically different things to the physicality of c fibres it becomes strained to view them as identical. Sure, I guess one could say that pain is not merely c fibres firing however, it could be asked, what then else is pain?

 

[Archaeopteryx]

The problem is that correlation does not entail causation and given that c fibres firing is not identical to the qualia of pain and qualia entails dramatically different things to the physicality of c fibres it becomes strained to view them as identical. Sure, I guess one could say that pain is not merely c fibres firing however, it could be asked, what then else is pain?

I think saying that "pain is c-fibres firing" is far too simplistic. A retina in a petri dish won't "see" anything when it is stimulated. The cells will simply fire, as they normally would, but without any sensation. All sensations seem to depend on the integrity of a much larger networks. At what point does a bunch of neurons firing become a system capable of something that we would recognise as vision? We don't know yet.

 

[Aelred of Rievaulx]

I think saying that "pain is c-fibres firing" is far too simplistic. A retina in a petri dish won't "see" anything when it is stimulated. The cells will simply fire, as they normally would, but without any sensation. All sensations seem to depend on the integrity of a much larger networks. At what point does a bunch of neurons firing become a system capable of something that we would recognise as vision? We don't know yet.

The philosophical argument extends towards this sort of supposition as well. Taken as a whole it has yet to be demonstrated that neural states are mental states and given how we interact it is highly unlikely that this will ever be demonstrated.

 

[Archaeopteryx]

The philosophical argument extends towards this sort of supposition as well. Taken as a whole it has yet to be demonstrated that neural states are mental states and given how we interact it is highly unlikely that this will ever be demonstrated.

What would be required to demonstrate this? We have already shown, convincingly I think, that mind and brain are integrated to such an extent that substance dualism is no longer tenable. What we have yet to understand, however, is how it happens that our brains are conscious and capable of feeling.

 

[Aelred of Rievaulx]

What would be required to demonstrate this? We have already shown, convincingly I think, that mind and brain are integrated to such an extent that substance dualism is no longer tenable. What we have yet to understand, however, is how it happens that our brains are conscious and capable of feeling.

The problem with statements such as these is that they confuse philosophy of mind terms. Substance dualism is certainly not in the arena anymore yet neither is type identity theory, a mental state does not have mass or location, rational relations are very different to causal relations. I honestly don't think anyone can answer your legitimate philosophical concern, who knows how the brain (or I'd rather say subject, if you please) is capable of consciousness and qualia...?

 

[GrowingSmaller]

The pain in my toe does not have a size or a location then?

 

[Aelred of Rievaulx]

The pain in my toe does not have a size or a location then?

You are confusing terms. Does the sensation "pain" have space? Mental states don't have locations, a belief in x is "on top of" a belief in y purely in a metaphorical sense.

 

[GrowingSmaller]

Yes it does have a space, right there in my toe! Otherwise I dont understand what you're getting at. Dont forget the origin of the terms "space" "location" size" etc, its right there in the phenomenal world - and that world is a mental (i.e. mind based) phenomenon.

 

[Aelred of Rievaulx]

Yes it does have a space, right there in my toe! Otherwise I dont understand what you're getting at. Dont forget the origin of the terms "space" "location" size" etc, its right there in the phenomenal world - and that world is a mental (i.e. mind based) phenomenon.

There's typically a distinction between mental things and physical things. The mental phenomena of pain and the physical fact of nerve ending and c-fibers, certainly it seems that they are related however the mental event cannot be said to be identical to the physical c-fibers firing because c-fibers have a particular shape which it doesn't make sense to assign to the mental event. Mental events have qualia, for instance; that is to say there is something like having pain, there is something like seeing blue, or something like happiness. To say that the physical neural networks are these qualia is to basically assign things from one ontological category onto another ontological category. It's problematic to say the least. At least most philosophers of mind seem to think it is, since Kripke.

 

[Archaeopteryx]

There's typically a distinction between mental things and physical things. The mental phenomena of pain and the physical fact of nerve ending and c-fibers, certainly it seems that they are related however the mental event cannot be said to be identical to the physical c-fibers firing because c-fibers have a particular shape which it doesn't make sense to assign to the mental event. Mental events have qualia, for instance; that is to say there is something like having pain, there is something like seeing blue, or something like happiness. To say that the physical neural networks are these qualia is to basically assign things from one ontological category onto another ontological category. It's problematic to say the least. At least most philosophers of mind seem to think it is, since Kripke.

Once again, I have to agree, but then disagree. It is far too simplistic to say that pain is c-fibers firing. The sensation depends on more than just c-fibers. You need an entire system that includes, but is not limited to, those c-fibers. That's why you can't isolate the sensation of redness in a petri tree by stimulating retinal cells with red light.

 

[GrowingSmaller]

C fibres are a part of the subcstnce then, just like the flour in the cake.

 

[Archaeopteryx]

Once again, I have to agree, but then disagree. It is far too simplistic to say that pain is c-fibers firing. The sensation depends on more than just c-fibers. You need an entire system that includes, but is not limited to, those c-fibers. That's why you can't isolate the sensation of redness in a petri tree by stimulating retinal cells with red light.

As an aside, this is probably why I approach cognitive neuroscience with greater enthusiasm than cellular neuroscience. Ultimately, it's all important to the broader goal of neuroscience and psychology, which is to understand the workings of the living brain.