The following is a paper from an intro to philosophy course i took at OWU.

At the heart of the debate over the nature of human beings, the existence of free will, and the validity of science there are two opposing viewpoints:  dualism and materialism.  Dualism is the belief that there are two kinds of substance that make up a person:  physical matter and more importantly a non-physical mind or soul.  Materialism disputes that claim and asserts that man and matter are one and the same, and that there is no mysterious, unobservable force which guides our actions.  Both viewpoints were arrived at in an attempt to put philosophy on firmer, more scientific ground.  The arguments of Descartes and Hobbes for dualism and materialism, respectively, are representative of the debate.

Though Socrates believed that in philosophy, nothing could be surely known without divine knowledge which no man possesses, Decartes believed some things could be known if you deduced them through the correct methods.  His method of doubt, a system whereby everything one can doubt one must throw out as untrue in order to get to what is absolutely true, led directly to dualism.

The argument is thus:  I cannot doubt I have a mind, but I can doubt I have a body.  Because what I can doubt cannot be the same as what I can’t doubt, my mind and body are not the same thing.  This argument seems valid based on Descartes’ reasoning.  First of all, if we define the mind (or soul, etc.) as that part of us which reasons and is aware (the mind is a thinking thing), we cannot doubt its existence because the act of doubting proves it exists.  The body, however, and all its senses and experiences, can be easily doubted.  Descartes gave several examples of instances when our physical experience and reality is not what it seems.  For example, the senses often deceive us;  parallel train tracks that seem to meet in the horizon never actually touch, distant pavement looks like water on hot days, etc.  Also, there are countless examples of insanity in humanity’s history-people become convinced of things that aren’t actually there, have false memories, and yet are totally convinced that these things are true.  Who am I to say what I see and experience is real and not the product of my own delusions?  Of course, too, we all dream, and in our dreams we are convinced of the reality of things we find absurd after awaking.  Finally, there is the possibility that all we experience physically is the whim of some all-powerful being or evil genius who wishes to keep us deceived of things by methods we are not clever enough to figure out.  To Descartes, it is obvious that we cannot trust our senses, and therefore we cannot trust any perception of the physical world, and its existence must not be taken as true.

If the body’s existence is doubtable but the mind’s is not, then by a principle known as Leibniz’s Law of Identity, the two things are not the same.  According to the law, two things are the same if and only if they have all of the same characteristics at the same time.  Descartes trusts this maxim as reason, and it leads to many other “proofs” of dualism.  For instance, during brain death, the body is alive but the mind is not.  Since they don’t have the same characteristics at the same time, they are not the equivalent.  Also, others can observe my body, but no one can directly observe my mind, so they are different.  Also, there is intentionality; thoughts are intentional because they are about something, whereas physical matter is not about anything and has no other meaning in and of itself.  Finally, there is the argument from perception; for instance, when we see a color and think about it, that color never appears anywhere in our brain to correspond with that thought, so clearly a physical color and a thought about a color are two different things.

Hobbes, on the other hand, attempted to rationalize philosophy by turning to materialism.  He reasoned that in order to understand societies, you need to understand what its made up of, people, and in order to understand people, you need to understand what they are made of, matter.  The idea of free will and an unobservable mind or soul is not compatible with his approach; if people are truly controlled by this “thinking thing” which cannot be studied, than society cannot be studied either.  In his mind, empiricism was a better method than rationalism.

There are several arguments for materialism.  One principle often brought up is Ockham’s Razor which is a powerful argument in favor of materialism given a few things are true.  According to Ockham’s Razor, all other things being equal, between two arguments the metaphysically simpler is most likely true.  That means that, assuming dualism and materialism are equally unproven, materialism is most likely true because it does not multiply something that is possibly one into two, as dualism does.

Also, there is the argument from evolution.  According to the theory of evolution, which is the most likely scientific explanation of the origin of life according to current evidence, man evolved from simpler organisms, which in turn evolved from even simpler one-celled organisms, which in turn evolved from non-ling proteins through some complex, but entirely physical process.  Now, if non-living proteins are purely physical and have no dualistic mind, then how can the physical process of evolution instill this non-physical soul into our ancestry somewhere along the line?  And if it did, at what point did it do so?  Are one-celled organisms in any part thinking things, or more complex organisms like fish or monkeys?  Was it gradual, or did a human being wake up one morning wake up dualistic while his undetectably more monkey-like father did not?

A similar argument can be made from the development of a new human being.  People start out as the fusing of two cells.  The cells combine genetic structure and then divide, again and again, and again, through wholly physical means.  A fetus develops, then it is born and as a baby it grows into an adult.  Now, if the adult has this soul, at what point did he acquire it?  The reasoning and implications are the same as above.  Dualism relies on some unknowable intervention in the creation or addition of a soul or mind to man; materialism needs no divine influence to describe the actions of man.

Materialism has been criticized, however. For instance, humans act in ways that cannot be readily explained by physical, observable principles.  One example is altruism.  There seems to be no physical, observable motivation for a person to do something for another without gaining  themselves, especially if they are harmed in the process.  And yet altruism seems to exist.  Hobbes would have to attribute it to an unconscious motivation in order to reconcile his theories, but the unconscious might as well be a soul.  It is unobservable and controls men’s actions, just as Descartes’ “thinking thing.”

Neither dualism nor materialism are complete or accurate in their description of humanity.  Moreover, both fail at being truly scientific.  Dualism is not scientific in any sense of the word; it denies the validity of observation (what all science is built upon) and puts forth a mere theory, the non-physical soul, with no evidence other than reasoning.  If we are not to trust our senses because they can be fooled, why should we trust our reason?  In dreams, just as one sees things that are not real, one acts and thinks in ways that seem absurd upon waking as well.  If reason is suspect then, who am I to say I’m not dreaming right now?  Also, everyone has had the experience of making a mistake in reasoning that seems absolutely plausible at the time but is later shown to be false.  Why is Descartes’ reason so infallible that his reasoning can be taken as absolute truth?

Materialism, too, is suspect.  Just because the soul can’t be proven from current observation does not mean that it’s not true, and Ockham’s Razor is therefore not a proof of materialism but merely an argument for it.  Hobbes, however, along with most materialists, take it as a truth as absolutely as the dualists take theirs.  Ockham’s Razor only tells us of what is likely to be, not what is.  Also, since the soul is supposedly unobservable, why couldn’t it develop during one stage or another of human evolution or growth?  Materialism is too quick to deny something it cannot prove or disprove.

The criticisms of both dualism and materialism are too strong to take either one as truth.  Instead, a better philosophy would combine the methods of both dualism and materialism but leave out their shortsightedness. It would use its own method of doubt, but instead of denying the validity of anything not absolutely known, it would assign a degree of trust to it depending on how likely it is true.  It would use materialism’s empirical approach to ideas to do so, but not deny anything it cannot prove or disprove and never assert anything to be absolutely proven, but instead proven to a high degree of probability.  This accepts Socrates’ ideas of human and divine wisdom while still saying it’s worthwhile to study things and try to find out their form; though you’ll never know for certain, you can get closer and closer to certainty forever.  This is the true scientific approach, basing theories on reason and then verifying them by empirical research to a high degree of probability, never putting absolute faith in any fact or idea.

For example, dualism throws out all ideas based on observation, because the senses could possibly be deceiving the observer.  Materialism ignores that possibility and draws conclusions based on those observations.  In the more scientific method, the senses are highly trusted if the observer is awake and not under the influence of anything likely to impair his judgement, and the observations are repeated by others under similar circumstances.  Thus, though no blind faith is put into the senses, a high enough degree of probability has been established to use the evidence they present to draw conclusions.

Take evolutionary argument for materialism.  Dualism would throw out the theory of evolution, because it’s based on observation, and the senses are suspect.  Materialism of course accepts evolution and says that since we began as purely physical matter and became as we are now through physical processes, we are wholly physical now.  A truly scientific approach, however, would say that evolution, which is most likely how the human species originated, does not deal with development of the mind or soul, and should not be extended to it until some direct or indirect evidence of it appears.  Perhaps indirect evidence already has, through theories of the sub-conscious, but no conclusions can yet be drawn.  As science becomes more advanced, it also becomes more aware of it’s limitations (the Uncertainty Principle in physics, for example), although that limit may be found infinitely far in the future.

This approach has obvious shortcomings.  For one thing, it’s hard for many people to accept that there’s nothing you can know absolutely for certain.  Though many meaningful things can be learned probabilistically, most people seem to have a need to know things for certain.  In religion, these certainties are taken as faith, and though faith is invalid in science it does matter in areas which science has not been able to approach, such as the existence of free will or god.  But in order to be able to assert things without falling into the same traps that Descartes and Hobbes have, one must realize human limitations and only give an idea the amount of certainty it deserves.