TORTOISE: Oh, you have captured quite well the essence of what might go on between the two of us in an admittedly hypothetical dialogue. I might well say all the words you attributed to me; and I have every reason to believe that you too could come forth with such utterances as you have just proposed. Thus, what have we come to? Ah, yes, I recall—in the hypothetical situation set up, I was in possession of a book, wherein were numerically recorded all the relevant data, neuron by neuron, taken from the brain of Albert Einstein the day of his death. On each page, we have: (1) a threshold value; (2) a set of page numbers, to indicate neurons linked to the present one; (3) the values of resistance of the linking axons; and (4) a set of numbers indicating how the wakelike “reverberations” of the neuron, which occur as a result of its firing, will alter any of the numbers on the page.
ACHILLES: By telling me what you have just said, you would have completed your aim of explaining to me the nature of the heavy tome in your possession. So we would probably have come to the end of our hypothetical dialogue, and I can imagine that we would soon thereafter bid each other adieu. Yet I cannot help making the observation that the reference you made in that hypothetical dialogue some possible future conversation in these gardens between the pair of us strikingly suggests the circumstances in which we find ourselves today!
TORTOISE: How coincidental! It surely is by pure chance.
ACHILLES: If you don’t mind, Mr. T, I’d like to know how this fictitious Einstein book could conceivably shed any light on the “mind-brain” problem. Could you oblige me in that respect?
TORTOISE: Willingly, Achilles, willingly. Would you mind, though, if I added a few extra features to the book, since it is hypothetical anyway?
ACHILLES: I can’t see why I should object at this point. If it’s already got a hundred billion pages or so, a few more can’t hurt.
TORTOISE: A sporting attitude. The features are as follows. When sound hits the ear, the oscillations set up within the drum are relayed to delicate structures within the middle and inner ear; these eventually connect to neurons whose duty it is to process such auditory information—thus we could call them “auditory neurons.” Likewise, there exist neurons whose duty it is to convey coded directions to any given set of muscles; thus, hand motions are caused by the firing of specific neurons in the brain linked indirectly to the muscles in the hand. The same can be said of the mouth and vocal cords. As our additional information, then, for the book, we’d like to have whatever set of data is required to know precisely how the auditory neuron will be excited by a given incoming tone, if we supply its pitch and loudness. And the other essential chapter in the book is the one that tells in what way the firing of any “mouth-directing neuron” or “vocal-cord-directing neuron” will affect the muscles of the organ in question.
ACHILLES: I see what you mean. We’d like to know how the internal structure of neurons was affected by any auditory input signal; and also how the firing of certain key neurons, linked to speech organs, would affect those organs.
TORTOISE: Precisely. You know, sometimes, Achilles, it’s good to have you around to bounce my ideas off of—they come back at me considerably cleaner than when I came out with them. Your naïve simplicity somehow complements my learned verbosity.
ACHILLES: I’d like to bounce that one off on you, Mr. T.
TORTOISE: How’s that? What do you mean? Did I say something untoward?
ACHILLES: Now, Mr. T, I assume that in the heavy tome under discussion, there would be numerical conversion tables, which accomplish precisely the tasks just set forth. They would give the neural response of each auditory neuron to any tone; and they would give the changes in mouth shape and vocal-cord tension as a function of the neurons linked to them by nerves in Einstein’s body.
TORTOISE: Right you are.
ACHILLES: How could such an extensive documentation of Einstein do anybody any good?
TORTOISE: Why, it could do no good for anyone, except conceivably some starving neurologist.
ACHILLES: So why have you proposed this stupendous volume, this prodigious opus?
TORTOISE: Why, only to tickle my fancy as I mused on mind and brain. But it may serve as a lesson to novices in the field.
ACHILLES: Am I one?