Online research in philosophy

Consider what the brain-state theorist has to do to make good his claims. He has to specify a physical–chemical state such that any organism (not just a mammal) is in pain if and only if (a) it possesses a brain of suitable physical–chemical structure; and (b) its brain is in that physical–chemical state. This means that the physical–chemical state in question must be a possible state of a mammalian brain, a reptilian brain, a mollusc’s brain (octopuses are mollusca, and certainly feel pain), etc. At the same time, it must not be a possible (physically possible) state of the brain of any physically possible creature that cannot feel pain. Even if such a state can be found, it must be nomologically certain that it will also be a state of the brain of any extraterrestrial life that may be found that will be capable of feeling pain before we can even entertain the supposition that it may be pain. It is not altogether impossible that such a state will be found... . But this is certainly an ambitious hypothesis. (Putnam 1967/1975, p. 436) The belief that mental states are multiply realized is now nearly universal among philosophers, as is the belief that this fact decisively refutes the identity theory. I argue that the empirical support for multiple realization does not justify the confidence that has been placed in it. In order for multiple realization of mental states to be an objection to the identity theory, the neurological differences among pains, for example, must be such as to guarantee that they are of distinct neurological kinds. But the phenomena traditionally cited do not provide evidence of that sort of variation. In particular, examples of neural plasticity do not provide such evidence.

The identity theory of mind holds that states and processes of the mind are identical to states and processes of the brain. Strictly speaking, it need not hold that the mind is identical to the brain. Idiomatically we do use ‘She has a good mind’ and ‘She has a good brain’ interchangeably but we would hardly say ‘Her mind weighs fifty ounces’. Here I take identifying mind and brain as being a matter of identifying processes and perhaps states of the mind and brain. Consider an experience of pain, or of seeing something, or of having a mental image. The identity theory of mind is to the effect that these experiences just are brain processes, not merely correlated with brain processes.

materialist that beliefs are not immaterial soul-states, I think that the conception of beliefs as brain states is badly misguided. I hope to show that "beliefs are brain states or soul states" is a false dichotomy. I am using the phrase 'beliefs as brain states' to cover several familiar theses: the token-identity thesis, according to which beliefs are identical to brain-state tokens; nonreductive materialism, according to which beliefs are constituted by brain states (as pebbles are constituted by..

Abstract Thomas Polger has argued in favour of the mind?brain type?identity theory, the view that mental states or processes are type?identical to states of the central nervous system. Acknowledging that the type?materialist must respond to Kripke?s modal anti?materialist argument, Polger insists that Kripke?s argument rests on dubious assumptions concerning the identity conditions of brain states. In brief, Polger claims that one knows that x and y are non?identical when one knows the identity conditions for both x and y. Replace x and y with ?brain states? and ?sensations? and it follows that one can know that brain states and sensations are non?identical only if one knows the identity conditions for brain states. But according to Polger, we do not know the identity conditions for brain states. Hence, we should not be so confident that brain states and sensations are non?identical after all. But Polger?s account is terribly flawed. Ironically, if Polger?s scepticism is warranted, then Polger himself has no good reasons to be a type?materialist. But more importantly, Polger?s scepticism regarding the identity conditions of brain states is deeply defective. We do, I submit, understand the identity conditions of brain states. In the end, I submit, Kripke is safe from Polger.

"Of Minds and Molecules" attempts to show the difficulties in mental-state brain-state monism. By exploring the differences in meaning between mental-state sentences and brain-state sentences, and by analysing the implications of the theory of the molecular composition of matter, a kind of dualism is arrived at that no scientist should feel uncomfortable with. It is a dualism without mental substance but it does not deprive mental states of their uniqueness. Arguments are given for the propriety of asserting causal connections and dependency relations between mental states and molecular states of the brain.

The claim of the multiple realizability of mental states by brain states has been a major feature of the dominant philosophy of mind of the late 20th century. The claim is usually motivated by evidence that mental states are multiply realized, both within humans and between humans and other species. We challenge this contention by focusing on how neuroscientists differentiate brain areas. The fact that they rely centrally on psychological measures in mapping the brain and do so in a comparative fashion undercuts the likelihood that, at least within organic life forms, we are likely to find cases of multiply realized psychological functions.