René Descartes is known to be the ultimate doubter. He believes that nothing we experience is trustworthy, because our senses do not show us the truth and we do not have the physical characteristics to observe the truth. From this he concludes that everything he experiences is inaccurate. Yet, he discovers that there must be existence within him. This is because he sees a distinction between the physical world and the non-physical world. Within Descartes' Meditations, he explains the fundamental differences between the mind and the physical world. The distinction is that matter is an unreflective, doubtful, and extended substance, meaning it extends into space. While the soul is a thinking and inextensible substance that cannot be doubted. My thoughts do not take up space, have no mass and cannot be divided, unlike matter. Descartes concludes that mind and body are two distinct things, since the mind could exist without a body and a body without a mind. Even if my body were only a product of my senses, I know for a fact that my mind, or soul, must exist in this universe. This leads Descartes to believe that it must exist. Since it has the ability to think that it exists, this shows that it has something existing at least in the non-physical world. “I became convinced that nothing exists in the world: no sky, no earth, no minds and no bodies. Doesn't it follow that I don't exist? No, I certainly exist if I am the one who is convinced of something” (Norman 341). This existence in the non-physical world is accessed through his mind. Furthermore, since it has the ability to be deceived by the senses, it must therefore exist. Thought is the only factor necessary for existence. If I am something that “doubts, understands, aff... middle of paper... like the brightness of the screen, I still have the awareness that it is the same computer with the same shape. Even though my mind, which is thinking these words, is independent of the fingers typing them, they are still interacting to write this article. With this physical essay, I can then share the realities that happen in my mind through the physical world and in the mind of another person, the reader. Because of this interaction between extended and non-extended substances, humans can influence each other's thoughts and exist together in both realities. Without this interaction, we would not have the beauty of what we call “human,” a being that can exist in both realities and share our ideas to progress towards understanding the truth. Works Cited Melchert, Norman. The Big Conversation. New York: Oxford University Press, 2011. Print.