PERCEPTION IS JUST ANOTHER RESPONSE
By J. J. RAY
School of Behavioural Sciences, Macquarie University, Australia
"The brain functions, not as a generator of consciousness, but as a two-way transmitter and detector; i.e. although its activity is apparently a necessary condition, it cannot be a sufficient condition, of conscious experience" -- Cyril Burt, 1968.
Burt (1968, 1969) has raised some challenges in his defence of mentalism that I would like to answer from a behaviourist perspective.
Since I wish to extend the arguments of Place (1956, 1969) and Smart (1959) and suggest that peculiarly mental events do not exist, I can only agree with Professor Burt's attack on emergentism. I first wish to challenge him, however, in his discussion of Identity (p. 31). He says:
"There could hardly be two things more disparate than a sensation, such as the blueness I see in the sky, and the electro-chemical processes taking place in my visual cortex as I lie in a meadow and gaze up at the zenith.".
While this is of course true, it is no refutation of the claim that all mental events are brain processes. The blueness is a characteristic of the sky. The electro-chemical processes initiated by the impinging of a blue light wave on my retina are characteristic of people. We would not expect the two to be the same. When we say we have an experience of blueness we do not mean that there is any such thing as a "blueness" in our heads. We rather mean that we respond to a blue object in the outside world.
Perhaps I should at this point define "response" in the way that I wish to use it. I mean a spike potential in a receptor cell, neuron, or muscle cell. By stimulus I mean anything which initiates such a response. Obviously, the response of one cell may be the stimulus for another and I see no quarrel with the usage which treats such a chain of responses as itself a superordinate response.
I next wish to disagree with Burt in his summary of Place as saying: "I observe the cortico-sensory process from within; the neurologist and the brain surgeon study it from without". As Burt rightly says, such a statement would imply the "aspect" theory - a modern idealist theory with which I and, I feel, Place, also disagree. I would summarize the realist position here as being: "When I see something (respond to light waves) the neurologist studying me from without observes certain events going on in my brain". I certainly do not "observe the cortico-sensory process" in any sense. I see objects and to see objects is a "cortico-sensory process". This, I feel, is Place's position. My "mode of access" is different from that of the neurologist because I see whereas the neurologist sees me seeing.
At risk of being repetitious, I would point out that this also answers Burt's question: "would Powell or Hirst declare that what I saw was really identical with my own brain process?" No, the nature of the brain process is (partly) influenced by what I see but to see the brain process of another person is not to see what that person sees.
Burt also mistakes the intent of Place's analogy with lightning. Place does not claim that the lightning an observer sees is "identical with a process within the observer's brain". What Place is pointing out is that one can engage in different operations to detect lightning and to detect electrical discharges and it is not unreasonable to conclude that, because electrical discharges always happen to be detectable where lightning is detectable, then lightning might just happen to be no more nor less than a particular sort of electrical discharge. In a similar way I can watch a neurosurgeon apply a stimulus to a particular brain area of a conscious patient and also ask that patient what he sees or feels. If he says he can see blue I might then say that the perception of blue is a response or responses in brain tract X - just as I say that lightning is an electrical discharge.
Burt's next question is: If "certain brain processes are identical with conscious experiences . . . . (how is it that) all these various processes . . . . prove to be much the same in every part of the brain and nervous system, whether or not they are accompanied by consciousness?" I might point out that this question is an empirical one which could only finally be solved by enumerating all types of brain events which are accompanied by consciousness and all which are not. Only then could we find out of what consciousness is made. (In the sense that we found of what lightning was made.) For all that, I would like to venture a prophecy of what we will find when we are able to make such a study. My prediction is that conscious brain responses are those which take place in the presence of, or linked with, that particular subcategory of responses known as "orienting responses" (Lynn, 1966).
To Professor Burt's arguments about the heuristic value of mentalism I have no fresh criticisms to add but would point out that the materialist monism I have outlined above is at least more parsimonious than Burt's position. Note that in claiming there is no uniquely "mental" class of events I am simply claiming that all of the phenomena we have been accustomed to call "mental" can be discovered to be in fact entirely "made up of" physical events. I am quite happy to continue using mentalistic terms such as "see", "think" or "idea" as long as they are understood to be summaries of physical events. A realist explanation such as this is, I believe, adequate to explain all the data and answer, at least in principle, all the questions. I have a suspicion, however, that the criteria of parsimony, heuristic value and explanatory power are not the only ones people use when evaluating a theory in this area.
Finally I would like to point out that it is an example of the classical ad verecundiam fallacy (i.e. an appeal to irrelevant authority) when Burt tabulates the opinions of physiologists on a philosophical issue.
BURT, C. (1968) Brain and consciousness. British J. Psychology, 59(1), 55-69.
BURT, C. (1969) Brain and consciousness. Bulletin of the British Psychological Society, 22, 29-36.
LYNN, R. (1966) Attention, Arousal and the Orientation Reaction. London: Pergamon
PLACE, U.T. (1956) Is consciousness a brain process? British J. Psychology, 47, 44-50.
PLACE, U.T. (1969) Burt on brain and consciousness. Bulletin of the British Psychological Society, 22, 285-292.
SMART, J.C. (1959) Sensations and brain processes. Philosophical Review, 68, 141-156.