René Descartes was a French philosopher and mathematician in the 1600’s. He has several noted works. There are few scientists, mathematicians and philosophers that the average person can quote. You may be able to quote Einstein’s famous equation, E=mc2, and a few others. More than likely you can quote one of Descartes’ main tenants, “I think, therefore I am.”
Descartes believed that everything, literally everything, could be explained by science and the considerations of mass and motion. In that quest, he imparted on an interesting thought experiment. His goal was to explain the self, that ethereal concept that some people call the soul, your own personal identity.
He took a simple tact. He tried to not think, to allow no thought, word or image to enter into his mind. The idea was, if he could not think, he could become matter itself and experience the universe in the raw. Well, I’m being loose with the facts there. I’m sure he knew at the outset that was impossible, but if he had been able to achieve the goal of not thinking, that would have been a significant result.
Try it yourself. Try to not think. Try allowing no thought, word, image or scent to enter into your mind. You will get the same result that Descartes did. You cannot do it. From that realization came his most famous phrase, “I think, therefore I am.” He is saying, because he thinks, and he is aware that he thinks, his existence cannot be questioned.
While it solves one problem, it presents a new one. I know I think. Therefore, I know that I am, but what about you? Since Descartes, a large portion of science has looked into existence and has had to acknowledge that existence itself may be purely subjective and merely an issue of perception. I perceive the ball as red, and you may also call the ball ‘red,’ but we have no way of proving that we both perceive the exact same thing. In your head red may look more like my green. We’ve just agreed that color, whatever it is, we both call red.
But it goes beyond that. As we now know that we may not be perceiving the same things, but we have merely agreed to call them the same thing, there is also the possibility that my whole world is simply a process of my own thought. That is, I call it a ball and I call it red because that is how I think of it. The ball and its color exist in my mind. There is no real evidence that the ball actually exists. Everything that I know, everything that I experience, is perceived in my own mind. My mind contains my entire world. Literally everything is within my own head.
So if everything is based on my experience, my perception, then it is possible that the ball is my own imagination only. I can touch it, feel it, weigh it. But all those sensations are realized only in my head. I can imagine its weight. I can imagine how it feels. There is no proof that it actually weighs that much, and feels that way, or that it is there at all. Given that, you may exist only in my imagination. It is possible that the ball, and you, and the Earth, and everything else is not real except within my own mind. I think. Therefore, I am, but that does not mean anything else is.
So right now you are thinking, “But wait. I think. Therefore, I am too.” But I cannot know that. I do not know what you think, or if you think, or if your thoughts are merely my own thoughts thinking about what you might be thinking. I cannot know if you see the same color that I see when we both look at something that we call “red.” As such, I cannot know if you actually think, and therefore, if you actually are.
You can leave a comment to this post, saying, “A Ha! While you were away, I wrote this comment, therefore I am.” But you cannot prove that I did not imagine you leaving that comment, and you cannot prove that you are not imagining this discussion at this very moment. Alas, humans cannot perform a Vulcan Mind Meld, and actually touch the thoughts of others.
Fear not. While it is difficult to escape the realization that all of reality is purely perception, I believe the ball is real and in front of us. And I believe we both perceive certain wavelengths of light in similar ways, and what we have agreed is “red” looks pretty much the same in your head as it does in mine. I believe you are real.