Diagram of the human brain

        

                                          brain neurons, showing their branching structure

The last few paragraphs describe only the dead ends that have been hit in AI. Other sciences searching for this same holy grail—a clear, evidence-backed model of human thinking—haven’t fared any better. Neurophysiology and behavioural psychology also keep striking out.

If a neurophysiologist could set up an MRI or similar imaging device and use his model of thinking to predict which networks of neurons in his brain would be active when he turned the device on and studied pictures of his own brain activities, in real time, then he and his colleagues could finally say they had formulated a reliable working model of what consciousness is. But on both the theoretical and practical sides, neuroscience is not even close to being so complete.

Patterns of neuron firings mapped on one occasion when a subject is performing even a very simple task unfortunately can’t be counted on. We find different patterns of firings every time we look. A human brain contains one hundred billion neurons, each one capable of connecting to as many as ten thousand others, and the patterns of firings in that brain are evolving all the time. Philosophers looking for a solid base for empiricism are disappointed if they go to neurophysiology for that base.¹²

Similar problems beset behavioural psychology. Researchers can condition rats and predict what they will do in controlled experiments, but many exceptions have to be made to their explanations of what humans in everyday life do.

In a simple example, alcoholics who say they truly want to get sober for good can be given a drug that makes them violently, physically ill if they imbibe even very small amounts of alcohol, but that does not affect them as long as they do not drink alcohol. This would seem to be a behaviourist’s solution to alcoholism, one of society’s most intractable problems. But alas, it doesn’t work. Thousands of alcoholics have kept on with their self-destructive ways while on disulfiram.¹³ What is going on in these cases is obviously much more complex than behaviourism’s best theories can account for. And this is but one simple example. I, for one, am not disappointed to learn that the human animal turns out to be a very complex, evolving, open-ended piece of work, no matter the model under which we analyze it.

At present, it appears that empiricism can’t provide a rationale for itself in theoretical terms and can’t demonstrate the reliability of its methods in material ways. Could it be another set of interlocking, partly effective illusions, like medieval Christianity, Communism, or Nazism once were? Personally, I don’t think so. The number of achievements of science and their profound effects on our society’s way of life argue powerfully that science is a way of thinking and living that gets results in the real world, even though its theories and models are constantly being updated and even though its way of thinking can’t logically justify itself.

However, sometimes models of reality from some of our once most widely believed and trusted scientific theories—for example, Newton’s laws of motion—have turned out to be inadequate for explaining more detailed data drawn from more advanced observations of reality. The mid-nineteenth-century views of the universe provided by better technologies and bigger telescopes led astronomers past Newton’s laws and eventually toward Einstein’s theory of relativity. Newton’s picture of the universe turned out to be naïve, but still quite useful on our everyday scale.

Thus, considering how revered Newton’s model of the cosmos once was, yet knowing now that it gives only a partial and inadequate picture of the universe can cause philosophers and even ordinary folk to doubt the way of thought that is basic to science. One can’t help but question whether empiricism is trustworthy enough to be used as a base for something so desperately important as a moral code for the human race. Our survival is at stake here. Science can’t even provide a rationale that can explain science itself.