Hand Waving is Not an Argument
|October 13, 2010||Posted by Barry Arrington under Intelligent Design|
In this article British neuroscientist Patrick Haggard has his assistant stimulate parts of his brain in a way that causes his fingers to twitch. Then the scientist announces in magisterial tones, “See, we have no free will.” Rubbish.
For decades we have known that stimulating certain areas of the brain with electrical impulses causes reactions in the muscles. No one has ever disputed this or that there is a material (in the philosophical sense of that word) cause-effect relationship between brain function and body function. It is one thing to conclude there is a material cause and effect relationship between the brain and body function, but it is something entirely different to assert that the existence of this material cause and effect relationship proves that human consciousness is an illusion and there is no free will.
Dr. Haggard has committed the logical fallacy of “affirming the consequent.” This logical fallacy takes the following form:
1. If A, then B
3. Therefore A.
1. If I get in my car I always go to my office.
2. I am at my office.
3. Therefore I got into my car.
Notice how the conclusion does not follow as a matter of logic from the premises even if both premises are true. It may be the fact that every time I get in my car I go one and only one place, i.e., my office. It may also be a fact that I am in my office. It does not necessarily follow that I got into my car to get to the office. I might have taken a cab or walked or gotten a ride from my wife. The error in affirming the consequent comes in failing to take account of the fact that A may not be the only sufficient condition of B. Factors other than A might also account for B.
Let’s see how Professor Haggard committed the logical fallacy of affirming the consequent.
1. Chemical/electrical reactions in the brain cause human actions.
2. Human actions occur.
3. Therefore, the human actions were caused by chemical/electrical reactions in the brain.
Not so fast. Might there not be other causes of human actions? Consider qualia for example. Apprehending that the sunset is red is a human action. Appreciating the “redness” and “warmth” of the sunset are also human actions. Can the subjective appreciation of the qualities of the experience of the sunset be reduced to the same chemical/electrical impulses that allow us to experience it in the first place? However one answers this question (and even many materialists believe the answer is “no”), certainly the question itself cannot be dismissed out of hand as Professor Haggard does.
I am not minimizing for a moment the hard problem of consciousness. But the puerile insouciance with which Professor Haggard simply waves the problem away is truly astonishing.