Wednesday, 3 June 2015

J. J. SMART’S ‘SIMPLEST EXPLANATION’ ARGUMENT

In ‘Sensations and Brain Processes’, J. J. Smart presents the ‘simplest explanation’ argument in defense of a form of physicalism called brain-state theory.  According to brain-state theory, there is an identity relation between mental states and brain states.  Particularly, every mental state is identical to a specific brain state.  While Hilary Putnam, too, propounds a physicalist perspective, in “The nature of mental states”, he highlights the failure of Smart’s brain-state theory to account for multiple realisability. The ‘multiple realisability’ of a mental state is the idea that different creatures with entirely different physiologies can experience the same mental state.  In “Mad pain and Martian pain”, David Lewis attempts to rescue brain-state theory with a move that mitigates Putnam’s concern with brain-state theory, allowing it to account for multiple-realisability.  However, I will argue that although the move accounts for multiple realisability of mental states, it complicates the physicalist brain-state theory to the point where it is no longer ‘more simple’ than dualism, undermining the premise on which Smart relies in his ‘simplest explanation’ argument.
The 'simplest explanation' argument, as presented by Smart in 'Sensations and Brain Processes' is a physicalist account of the interaction between mind and body.  Smart would like to establish “that there are no philosophical arguments which compel us to be dualists”[1].  Smart claims that the relation between ‘sensations’ and ‘brain states / processes’ is one of identity, where ‘sensations’ are mental states, and each mental state is identical to a particular brain state. He takes a step further, and says that all “sensations are nothing over and above brain processes”[2].  There is only one type of stuff, that which can be described by physics.  The mental is physical, in Smart’s view. 
Smart contrasts this with dualism, which he describes as requiring “ultimate laws [that] would be like nothing so far known in science”[3] to explain the interaction between a non-physical mind and the physical body.  He uses the example of orthodox geologists’ and paleontologists’ theories for the age of the Earth to illustrate two “empirically equivalent” theories, and the principle that when two theories are empirically equivalent, it is more reasonable to believe the simpler theory.  “Empirically equivalent theories” are theories that both successfully account for empirical evidence.  If we accept this principle of theory choice, and both physicalism and dualism are empirically equivalent, then for Smart, it follows that it is more reasonable to believe physicalism.
In 'The Nature of Mental States', Putnam introduced a concern with Smart’s brain-state theory that would undermine his claim that it is empirically equivalent to dualism. Putnam argues that Smart’s brain-state theory is unable to account for the ‘multiple realisability’ of mental states.  The ‘multiple realisability’ of a mental state is the idea that different creatures with entirely different physiologies can experience the same mental state.  Putnam characterizes Smart’s brain-state theory as requiring each mental state to have a specific physical-chemical state.[4]  Then, given the transitivity property of identity, brain-state theory would entail that for a creature with physiology different from mine, it would not be possible for both I and that creature to experience the same mental state.  This is a problem for Putnam, since he believes that there is some sense in which my pain is identical to the pain of a creature’s whose physiology differs from mine, while he does not want to permit the existence of pain as a mental state that exists distinctly from our physical bodies.  Putnam assumes that mental states are “multiply realizable”, and so in his view, Smart’s brain-state theory cannot account for it.  This undermines Smart’s physicalism as an empirically equivalent theory to dualism, which is one of the premises on which he builds his ‘simplest explanation’ argument.
In David Lewis’ “Mad Pain and Martian Pain, Lewis proposes a version of brain-state theory that can account for the multiple-realisability concern introduced by Putnam.  Like Smart, Lewis identifies each mental state with a particular brain state.  However, he agrees with Putnam that multiple-realisability is possible, and thus a concern.  Lewis uses the example of “the Martian who sometimes feels pain just as we do, but whose pain differs greatly from ours in its physical realization[5]”.  Smart’s brain-state theory cannot account for the Martian’s pain, since a Martian’s physiology differs from ours.  Smart’s theory does not identify the Martian’s pain as our pain.  To account for multiple-realisability of pain in this comparison, Lewis defines mental states as relative to a population: “The Martian is in pain in another sense, or relative to another population”[6].  For Lewis, an individual X is part of an appropriate population if:
(1) X is ‘us’,
(2) X belongs to it,
(3) X is not an exception within in, and
(4) the population is of a natural kind.[7] 
This move to relativize mental states permits the brain-state physicalist to say that I experience human pain, the Martian experiences Martian-pain and any individual member that is not an exception within its population experiences mental states relative to its population.  That is, the introduction of population-relative mental states to brain-state theory accounts for multiple-realisability, addressing Putnam’s concern.
Although Lewis’ hybrid theory reconciles the physicalist brain-state theory with concerns of multiple realisability, it undermines Smart’s premise that physicalism is more simple than dualism.  Lewis’ modification to brain-state theory can only be achieved with the definition of an appropriate population for each individual.  Lewis proposes four criteria and provides examples of how to use them to determine the appropriate population for the following:
·         you/I, unexceptional humans
·         the Martian
·         the madman, who feels pain just as we do, but who differs greatly in its causes and effects, and
·         the mad Martian, the Martian analog to the madman. 
In the case of you/I, Lewis says that the four criteria “pull together”.[8]  In the case of the Martian, Lewis writes that criterion (1) is outweighed by the other three.[9] In the case of the madman, criterion (3) is outweighed by the rest, so the madman is conveniently considered part of the population of ‘mankind’.[10]  In the case of the mad Martian, criteria (2) and (4) together outweigh either (1) or (3) by itself. [11]   I list this out to show that there is no consistency in the use of the four criteria for determining an individual’s appropriate population.  We are left with the possibility that there may be no clear definition of an appropriate population for some individuals.  Now consider criterion (3), that X is not an exception within a population.  The term ‘exceptional’ is also vague. Imagine a population with some set of arbitrary Type-Z properties who are ‘exceptional’ because they are outnumbered by unexceptional ‘unexceptional’.  There can easily be any number of similar Type-Y, Type-X, etc, populations with various sizes, but that are still outnumbered by ‘unexceptional’ humans.  This shows that there may be varying degrees as well as varying types of what is meant by ‘exceptional’.  Now imagine the situation where the population of Type-Z individuals breeds rapidly to outnumber the people who are unexceptional.  Because they outnumber the other types of human populations, they are now ‘unexceptional’.  Would this mean that there is something indexical about the concept of ‘unexceptional’?  If so, then this further complicates the determination of an ‘appropriate population’ for an individual.  By introducing population-relative mental states, Lewis enables brain-state theory to account for multiple realisability, but the result is a vague and more complicated physicalist theory.  Smart’s ‘simplest explanation’ argument would fail with Lewis’ modification.  Multiple realisability as presented by Putnam is attractive, but it need not necessarily be accepted. Brain state theorists will still need an account for mental states as experienced by creatures not physiologically similar to us, but it should not be at the expense of a consistent theory for physicalism.
Bibliography
Lewis, David. 1980. “Mad pain and Martian pain”, in Readings in the Philosophy of Psychology, Vol. I. N. Block, ed., Harvard University Press, 1980, pp. 216-222.
Putnam, Hilary. 1975. “The nature of mental states”, in Philosophical Papers, Vol. 2, Cambridge University Press, 1980, pp. 429-440.
Smart, J. J. C. 1959. Sensations and brain processes. The Philosophical Review 68 (2) (Apr.), pp. 141-56.



[1] Smart, J. J. C. 1959. Sensations and brain processes. The Philosophical Review 68 (2) (Apr.), pp. 143
[2] Smart, J. J. C. 1959. Sensations and brain processes. The Philosophical Review 68 (2) (Apr.). Pp. 145
[3] Ibid. Pp. 143
[4] Putnam, Hilary. 1975. “The nature of mental states”, in Philosophical Papers, Vol. 2, Cambridge University Press, 1980, pp. 436
[5] Lewis, David. 1980. “Mad pain and Martian pain”, in Readings in the Philosophy of Psychology, Vol. I. N. Block, ed., Harvard University Press, 1980, pp. 216
[6] Ibid. Pp 221
[7] Lewis, David. 1980. “Mad pain and Martian pain”, in Readings in the Philosophy of Psychology, Vol. I. N. Block, ed., Harvard University Press, 1980, Pp 220
[8] Ibid. Pp. 220
[9] Ibid. Pp. 220
[10] Lewis, David. 1980. “Mad pain and Martian pain”, in Readings in the Philosophy of Psychology, Vol. I. N. Block, ed., Harvard University Press, 1980, Pp 220
[11] Ibid. Pp 220



****
There are some inaccuracies in this.  Sorry about that.  Homework assignments are rushed.  Anyway, this got me an A, so hope it helps.
There was an error in this gadget