The central issue in the "mind body issue" or Cartesian Dualism focuses upon the question of how the two realms interact. How does a "spirit" or "mind" move the material items of reality?
Descartes had a theory in which he tried to localize the interaction between the mind and the body, but unfortunately it did not make sense. Descartes never really answered the issue adequately. It seems that the question of how these two radically different realms interacted was not just difficult but also scandalous to explain or even to understand.
However, Descartes concept of subject and object is one which cannot be dispensed with.
The fact is that the "known" cannot be known independently of the "knower."
The subject object dichotomy is a necessary and an inevitable feature of our worlds.
Complete idealism, to believe only in the "spirit" or "ideas" as comprising reality, is difficult to endorse. We each have a tendency to naturally believe in the duality of human existence in general and personal existence in particular.
The "knower" has to be seen as an essentially embodied entity.
It is true that regarding Descartes conclusion, "I think therefore I am", A. J. Ayer and Bertrand Russell had concluded that Descartes simply did not go far enough. They propose that he should have concluded, "I think therefore there are thoughts."
But this is counter to everyone's experience in a way of speaking. Like Descartes, we cannot grasp the "known" being known independently of the "knower."
Dualistic existence was not only inescapable for Descartes, but is also so for us.
The interesting and often overlooked feature of Descartes conclusion, "I think therefore I am" is its dualistic nature. He proposed what has become the center of Western Philosophy, that is the theory of knowledge, and philosophy essentially starts with what can I know and not with the question of what is there or what can I know.
His epistemologic reduction of "I think therefore I am" consists of a first person singular point of reference and inherent in the conclusion is the subject object dichotomy. He assumes that there is a "knower" (I) and that there is the "known" (I exist).
It should also be pointed out that Descartes conclusion is autobiographical in nature.
Interestingly, an overlooked and yet highly significant literary reality is that Descartes works were penned in the first person singular. Descartes quest was not just the quest of an intellectually curious individual, but it was the quest of someone who genuinely wanted to understand his own existence, the extent of what he could know and ultimately his relationship to the external world.
Today philosophers point out that the focus has shifted away from the epistemologic quest toward the metaphysical. Yet the study of Descartes should still be regarded as invaluable. This is the case for a number of reasons.
First, we must understand Descartes historical role in philosophy. His work reflects a high point and a turning point in the philosophical task.
Second, Descartes work is intrinsically and personally compelling. He follows the path of speculation in a compelling manner for each of us. In some shape, form or fashion, Descartes questions are our own questions and his struggle is at some point our own. The fact is that at some point in his life, every thinking person has to stand back and ask himself the questions, "How can I know if all of these things which I have endorsed as true are genuinely true and how can I make the answers my own?"
In fact, I would even argue that asking and answering these questions is part of the process of healthy individuation in human development and may even lie at the core of the often trivialized "mid life crisis" of individual existence.
Finally, Descartes poses the question, "What am I?" in his work. In fact this question constituted the core of Descartes work. The very question gives the idea that I am independent of my boy and the parts which I have, so to speak. In other words, Descartes verbalizes our recognition, whether conscious or subconscious, that there is more to us than "stuff".
