What makes for a good scientific theory? A summary can be found here:
Theories... are broad explanations for a wide range of phenomena. They are concise (i.e., generally don't have a long list of exceptions and special rules), coherent, systematic, predictive, and broadly applicable.
If a putative theory is self-contradictory, it is a non-starter. Any theory must be simpler than the phenomena it purports to explain. This is referred to as “explanatory power”, which includes:
it changes more "surprising facts" into "a matter of course"
and as a result gives us deeper insight into the nature of the subject phenomena. Finally, any valid theory must make predictions that are confirmed by experiment and observation.
Great scientific theories explain an entire realm of observation with just a few principles. For example, Newton’s Laws of Motion, combined with his Law of Gravity, explain the orbits of the planets, the trajectories of projectiles, the tides, and the motions of billiard balls, just to cite a few examples. Maxwell’s four equations govern all of electromagnetism, and enable engineers to design (predict) all matters electronic. So these theories have great explanatory power.
Now let’s take a look at Scientific Materialism, which I shall refer to here as “physicalism” for short. Specifically, let’s look at how physicalism applies to our ordinary subjective experience of consciousness.
The central principle of physicalism is that every physical effect must have a physical cause. From quarks to quasars, to the quirks of human behavior, there can be no exception. Regarding human behavior, every human action is caused by the firing of motor neurons. This in turn is caused by the firing of neurons in the brain, which in turn is caused by the firing of neurons at sensory inputs, interacting with brain structures such as memory. There cannot be a spiritual “ghost in the machine” magically causing nerve impulses. All human activity must be physically explainable.
Where does this leave the subjective awareness that we refer to as consciousness? According to physicalism, consciousness is an “epiphenomenon” of all this neural activity. This “theory” lacks explanatory power — the "surprising fact" of consciousness is still a surprising fact. It provides no insight. It is not an explanation at all. It is an excuse for not having an explanation. In no other realm of science would any observed phenomenon be labeled an epiphenomenon. If it were, such a suggestion would be met with derision — Imagine, smoke being referred to as an "epiphenomenon" of fire!
This epiphenomenon theory makes a prediction — consciousness cannot be the author of any act. All action is caused by the purely physical activity of our neurons. All observed phenomena is accounted for without this "epiphenomenon" — consciousness is merely an accident, along for the ride. If this theory were true, our experience would be that of a passive observer in a meat robot. This of course is not the case since any healthy person can move at will. Therefore the theory of consciousness espoused by scientific materialism is dashed upon the rocks of an easy observation.
Some physicalists are fond of speculating as to how and why consciousness may have evolved. However, according to physicalism, consciousness cannot influence behavior. Its existence or lack thereof cannot then be subject to forces of natural selection. So evolution could play no role in the origin of consciousness. Therefore, according to physicalism, consciousness has no apparent cause and no apparent purpose. Its existence is neither predicted nor explained.
Conclusion: Scientific materialism fails as a theory of consciousness.
Previous Atheist Digest Diaries: Intro and How I became an Atheist By Xneeohcon Glossary By Rieux On Christian Claims to Moral Superiority By Xneeohcon Debunking Dogmas, Part I: Creationism By wilderness voice The believers' path to Atheism By Brahman Colorado Atheist Digest ’10: Ben Stein is a Moran: The Retrospective Improbability Fallacy By XNeeOhCon Upcoming Scheduled Diaries: Wed. September 1st, About 5:30 PM PST – Conclusion Diary Stay tuned for diaries from other users including Rieux, Rfall, Something the Dog Said, and Warren S (Look for "Atheist Digest '10" in the Tags and Diary Title)