Descartes’ central project in Meditations is to provide a foundation for the certainty of knowledge. His project is to show that the real source of knowledge lies in the mind and not in the senses and that is why Meditations is also a critique of empiricism. His aim includes making a clear distinction between mind and body and providing the proof for the existence of God. The objective is to reconcile the church and science by providing each a separate domain to work. He begins his project by doubting everything as he wants to find the indubitable basis of knowledge and then wants to begin constructing the knowledge from there up. He is trying to solve the objections raised by the skeptics about the certainty of knowledge and about the existence of God. In Meditation he addresses problems like how do we acquire true knowledge about the world; how body and mind relates with each other and with our experiences; what is the extent of our ability to know the truth, etc.
Descartes begins his endeavor of finding the certainty of knowledge by devising his famous method of doubt. He first declares that our senses cannot be a reliable source of knowledge so everything we know from our senses can be doubted. He develops his method of doubt regarding the sensory knowledge by putting forward the arguments of dream and evil demon. In his dream argument, he describes that we perceive things in dreams similar to the real world. The sensations we experience while dreaming are not different from the ones we experience while we are awake. There is nothing that can distinguish our dream experiences from the experiences we have when we are not asleep. Our sensory experiences cannot be trusted as we do not know that the things we perceive are exist in reality or just present in our dreams. In other words, we cannot know for sure which experiences are true and which are not as there is no marked distinction between our waking experiences and our dreaming experiences.
Similarly, to strengthen his method of doubt he brings forth another argument, the argument of a deceiving God or an Evil Demon. He contends that, not only we can doubt our sensory experiences, even the things we consider certain like the mathematical truths are open to doubt. To make his point, he proposes the idea of a deceiving God. He claims that as God is omniscience and all-powerful, He can deceive us even about the mathematical truths. There are no reasons to disbelieve that we are being deceived by God about geometrical certainties. To answer the objection that God is benevolent and perfect, and such a God would not deceive us, he modifies his argument by replacing God with an Evil Demon. He opines that what if there is an Evil Demon who is deceiving us about the basic structural and geometrical facts regarding the real world. The presence of such an evil demon is not impossible and if this is so, then even the mathematical realities come under the shadow of the doubt.
Consequently, if the certainty of our sensory experiences, as well as our mathematical truths, can be doubted, then what is left that cannot be doubted. Is there anything left which is still indubitable? To answer this question, Descartes proposes his famous “Cogito argument”. According to the argument, one can doubt everything but to doubt one has to exist. Without "existence" one cannot doubt, and that is why one’s existence is indubitable. The Evil Demon can deceive one about everything. But to get deceived by the Evil Demon one’s existence is a must. No matter how powerful the Evil Demon is, “Cogito” cannot be deceived about his own existence. So, by using his method of doubt, Descartes finally acquires something indubitable. The “Cogito” or “I” exist indubitably because it can think about the Evil Demon and it can doubt, but to do that it has to exist. One's body, one's senses and every other thing can be doubted but not one's mind. One's mind is the foundation of one’s true experiences as it is indubitable, but not one's senses as knowledge from them can be put under doubt. It is possible and conceivable that one exists without one's body, but one cannot be certain about one’s existence if one is not thinking. Cogito can exist without an extended physical body, but cannot exist without thinking. Consequently, Descartes claimed that Cogito is a thinking being.
In a similar manner, Descartes moves from the indubitably of Cogito further ahead towards the existence of God. He contends that Cogito has the idea of a perfect God, but Cogito himself is not perfect. Resultantly, Cogito cannot be the cause of this idea of a perfect God because imperfect being cannot cause the idea of a perfect being. The only possible explanation, in the eyes of Descartes, is that God himself placed this idea of a perfect God. This line of reasoning entails that God exists and His presence cannot be doubted as well. Furthermore, if God exists and he is not a deceiver than mathematical truths of our world also real. Our experiences arise from the external world and if the external world does not exist, then it would be a deception on the part of God. But God is not a deceiver so it entails the conclusion that the external world really exist. Descartes adopts this line of reasoning to conclude that though mind is the reason of our experiences, yet in addition to mind, matter and material world exist as well.
Then, Descartes articulates the argument regarding the distinction of mind and body. He believes in the duality of mind and body. He contends that the mind is sharply distinct from the body as there is nothing common between them. Mind and bodies differ even in most basic attributes and, so he concludes that mind and boy must be different from each other. The other reason he gives about mind-body dualism is that bodies are extended things, i.e. they extend in space while the mind is not an extended thing. So, extended and non-extended things cannot be one single thing, and this further strengthens his argument of mind-body dualism. Descartes' wax argument is another way of showing the duality of mind and body. A particular piece of wax has certain physical attributes, it has dimensions, it has a certain hardness, and it has a certain smell, etc. However, if we bring that piece of wax near a fire, it would melt. Its physical appearance, its color, its dimensions, and all the physical attributes would change. But we still consider it the same piece of wax even though all our sensory data is different for the solid and melted piece of wax. According to Descartes, we infer that the piece of wax is the same one not through our senses, but by using our rational abilities. The presence of wax shows that there is a physical object out there, but our mind cannot interact with it directly and we cannot trust our senses. We can perceive the real nature of things only through our thinking and rational faculties. Consequently, we are able to perceive the same piece of wax solely by our mind; even after all its physical attributes are changed.
Descartes’ method of doubt has been very persuasive in determining the foundation of knowledge. Descartes endeavors to doubt everything in order to find something that is beyond doubt. If something cannot be doubted with all our efforts, then it must be certain. Once we have the certain foundation of reality we can build up from there. The argument, indeed, has a very strong appeal. No matter how persuasive this method of doubt looks it does have some flaws. Descartes is over emphasizing the flaws in our sensory experience. Just because sometimes our senses are deceived does not entail that every experience gathered through them is false. Most significantly, to doubt everything we must doubt that we are actually doubting. This will lead us to an unending cycle of regress, and this objection cuts right through the heart of the method of doubt. Moreover, to limit knowledge to only those things about which we are absolutely certain is a very narrow approach to gather knowledge. We can have knowledge about things even without absolute certainty.
Lastly, even Descartes second project, i.e. the duality of mind and body runs into serious troubles. If body and mind are as distinct as Descartes claims them to be, then how they interact with each other? How an immaterial mind can interact with and affect a material body and vice-versa. Descartes fails to give any satisfactory reply to this objection. It is clear from our day to day experience that body and mind interact with each other. So, we have to conclude that our bodies and minds are not as distinctly separates as Descartes proposes.
Descartes, Rene. Meditations and Other Metaphysical Writings. Penguin Classics, 1999.
Descartes, René. Meditations on First Philosophy. 1641.