Descartes' "I think therefore I am," statement fascinates me. As does Cartesian dualism. I dont know of a more contentious, debated, or philosophized about idea. Are many recent philosophers right in totally disregarding and criticizing Descartes? And just what is consciousness? What is our mind? If I think a thought, is this thought not entirely extraneous to my body, and generally wholly individual to me?
I'm especially interested in whether we all really have consciousness, can have knowledge etc; or whether it is nothing more than chemical reactions, and whether knowledge is possible for each person, or whether it is entirely socially constructed.
I would say that Cartesian
substance dualism is generally inadmissible unless one is a Christian or a New Age spiritualist of some sort (and if I remember correctly, one of the few modern philosophers to provide a spirited defense of substance dualism is Alvin Plantinga, a Christian theorist who also supports intelligent design). The idea that the mind (or soul) and the physical brain/body are two fundamentally different substances is certainly reconcilable with these belief systems but not with much else.
Property dualism is generally more accepted in 20th/21st century philosophy because instead of stating that there is a physical distinction between the mental and the physical, it states that while only physical objects exist, these can contain both mental and physical properties. This refutes straight-up materialism by stating that the mental properties are not irreducibly physical. In other words, a pain sensation or the experience of seeing red cannot be explained merely by looking at the physical reactions occurring in the brain.
As far as consciousness goes, you can say that there's a distinction between the "easy" and "hard" problems of consciousness. The former is what we regard as things that can be objectively observed (i.e. how taking anti-depressants alters your brain chemistry and thus alters your overall behavior). These are relatively easy to explain because there exists a readily observable functional role, a clear cause and effect. The latter is something a bit more abstract (some would even call it nonsensical) because it asks
why and
how qualitative phenomenal experiences come to be. To use a classic example, I can wonder what it is like to be a bat all I want, but so long as I am a human, all this will amount to is speculation. A physicalist would simply argue that the hard problem is holistically solved by the easy problems (as John Searle says in his view of biological naturalism). A property dualist would solve it by saying that this "what is it like" aspect is irreducible.
I recommend reading
The Conscious Mind and other works by David Chalmers for the best defenses of dualism. The main alternatives are a variety of physicalist/materialist views, including type/token identity theory, various forms of functionalist theory, eliminative materialism, and the aforementioned biological naturalism.
I would generally say that modern philosophy is correct in its criticism of Descartes. At best his work created the framework for some good mental exercises in skepticism (Evil Demon, Brains in Vats, and so forth) which nonetheless are of little practical use. Admittedly he managed to synthesize his philosophy with Christian theology quite well, but saying that his original arguments are strong would require, at least by my calculation, a pretty large leap of faith. It is not possible to objectively observe the mind and so saying that it is composed of a fundamentally different substance than physical bodies appears foolhardy and as previously stated, seems to be rooted to at least some degree in religious tradition. Ultimately the question of consciousness appears to be one of insurmountable difficulty. I could say to you that our mental events are just emergent properties of physical processes in our brains, but if they are merely emergent, then they cannot have any causal role in our lives. This seems highly counterintuitive if you think about it. The questions about how consciousness comes to be are among my favorites in philosophy but they appear among the most difficult.
http://plato.stanford.edu/entries/consciousness/
This is a pretty in-depth article on the subject, and if you scroll to the bottom there are many related topics.
You were the one who tried to make the point in the first place...
