Online research in philosophy

Based on the technique of pressure blinding of the eye, two types of after-image (AI) were identified. A physicalist or mind/brain identity explanation was established for a negative a AI produced by moderately intense stimuli. These AI's were shown to be located in the neurons of the retina. An illusory AI of double a grating's spatial frequency was also produced in the same structure and was both prevented from being established and abolished after establishment by pressure blinding, thus showing that the location was not more central. The illusory AI was predicted from the known non-linearity in the retina and this is the first case of a clear cut type-type identity of a sensation and a neural process. Some implications for the concepts of the explanatory gap between neurology and consciousness and multiple neural realizations of conscious states and topic neutrality are discussed.

It is argued that the explanatory gap argument, according to which it is fundamentally impossible to explain qualitative mental states in a physicalist theory of mind, is unsound. The main argument in favour of the explanatory gap is presented, which argues that an identity statement of mind and brain has no explanatory force, in contrast to "normal" scientific identity statements. Then it is shown that "normal" scientific identity statements also do not conform to the demands set by the proponent of the explanatory gap. Rather than accept all such gaps, it is argued that we should deny the explanatory gap in a physicalist theory of mind.

Mind body, not a pseudo-problem, by H. Feigl.--Is consciousness a brain process? by U. T. Place.--Sensations and brain processes, by J. J. C. Smart.--The nature of mind, by D. M. Armstrong.--Materialism as a scientific hypothesis, by U. T. Place.--Sensations and brain processes: a reply to J. J. C. Smart, by J. T. Stevenson.--Further remarks on sensations and brain processes, by J. J. C. Smart.--Smart on sensations, by K. Baier.--Brain processes and incorrigibility, by J. J. C. Smart.--Could mental states be brain processes? by J. Shaffer.--The identity of mind and body, by J. Cornman.--Shaffer on the identity of mental states and brain processes, by R. Coburn.--Mental events and the brain, by J. Shaffer.--Comment: mental events and the brain, by P. Feyerabend.--Materialism and the mind-body problem, by P. Feyerabend.--Materialism, by J. J. C. Smart.--Scientific materialism and the identity theory, by N. Malcolm.--Professor Malcolm on scientific materialism and the identity theory, by E. Sosa.--Rejoinder to Mr. Sosa, by N. Malcolm.--Mind-body identity, privacy and categories, by R. Rorty.--Physicalism, by T. Nagel.--Mind-body identity, a side issue? by C. Taylor.--Illusions and identity, by J. M. Hinton.--Bibliography (p. [259]-261).

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.

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.