Even though one is bombarded every day with experiences that seem to be from the outside world, it is important to reflect on their validity and source before coming to a premature conclusion using only intuition. There is a general consensus that there is an outside world, which is what people feel and navigate through every day, and which has certain characteristics. Nevertheless, if one stops to critically examine the evidence that there is for this conclusion, one can see that many other interpretations are also possible. Most philosophers do not negate the different experiences and the possibility of the conclusion that there is an outside world apart from the thinking person. On the other hand, the critical aspect of this issue is how one can be sure that it actually exists and is not only a figment of one’s imagination. One of the most influential philosophers that analyzed this was René Descartes, who proposed that there was no actual way to demonstrate the existence of the outside world, especially in his Discourse on the Method. Nevertheless, there are other thinkers, like G. E. Moore, who believe that proving that an outside world exists would be as simple as raising one’s two hands. The omnipotence of imagination renders any evidence of the outside world inconclusive as to whether it really exists or not, much less its characteristics.
The greatest philosopher to be skeptical of the outside world was René Descartes, who believed that there was no way to distinguish whether everything that one experienced was in one’s mind or not, separating this instance from one’s body. In his Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences, one can see right from the title that he was trying to obtain truth through the use of reason. A consequence of this is that he separates his mind from his body, formulating the res extensa and the res cogitans as separate substances. Therefore, the issue would be if there was any way for the res extensa to be assured through the res cogitans.
Here one can begin to see the main problem with this type of skepticism: it was very radical. He was looking for something that would be completely uncontested. In this sense, Descartes wrote, “I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be somewhat” (2008). This is why he believes that his thinking is the reason for his being: cogito ergo sum. By giving predominance to the mind, as this is the only thing that he believes he can be sure of, he dismisses the body as being a possible figment of his imagination.
His only guarantee for existence is his thinking; everything else, he leaves up to God. For him, the only way that one could ensure that the external world exists and has certain characteristics is that a non-deceiving God assures this truth. He even states that there could be an evil demon leading him to perceive the outside world, something related to the modern brain in a vat problem. For Descartes, his sensations should all put under question, leading to the impossibility of the discovery of the outside world. For him, any test that a person could hold and perform in his or her mind would have to come into question, as there would be no way to be certain that it had actually happened. The whole procedure could simply be a figment of one’s imagination and not really occur in the outside world.
Against this type of skepticism, G. E. Moore provides a very simple demonstration of the existence of the external world, by only raising his two hands. He believed that, in this way, he had “proved ipso facto the existence of external things” (Moore, 1993, p. 166). By going through three simple steps, he contends that he has found a “perfectly rigorous proof” (Moore, 1993, p. 165) in order to contradict Descartes’ negation of the external world. The first of these would be that the premise and the conclusion are different; then, that the premise is a fact, not a belief; finally, that the conclusion comes from the premise. Therefore, Moore contends that he can rigorously demonstrate the existence of outside things through this proof.
Nevertheless, this seems to be misleading. He does not really ascertain that an outside world exists as his conclusion, but that “merely Two human hands exist at this moment” (Moore, 1993, p. 166), something that is obviously very different. By Moore moving his hands, making gestures and speaking, he does not even believe that he can really determine that the outside world exists, merely stating that two hands exist at that moment. However, if one believes the hands to be separate for the mind, one could lead this towards the conclusion that the outside world exists.
Interestingly, one of his greatest foundations is in Immanuel Kant, another person that also established a complicated relationship between the outside and the inside worlds. Of the great German philosopher, he states, “it is notorious that he himself held that things which are to be met with in space are not 'external'” (1998, p. 159). Therefore, he mentions Kant’s thinking and then dismisses the great implications that this has.
In this sense, Kant states that the only way to know an external world would be through the establishment of a self. “The mere, but empirically determined, consciousness of my own existence proves the existence of objects in space outside me” (Kant, 1998, p. 327). This is an interesting point of view, because he postulates the self as the difference with respect to the rest of the objects around him. For him, the existence of the external world would be demonstrated by the fact that there is a self.
Nevertheless, Descartes could see this as being an illusion as well. In this sense, the existence of the self would be really limited to the assertion that one thinks, a matter of res cogitans, not res extensa. The experience of the body as an individual would thus be a part of the res extensa, which could all just be a part of the res cogitans’ imagination.
In conclusion, the power of imagination and the intellect implies that one cannot really be sure if the outside world really exists. Descartes is the great presenter of this dilemma; by dividing the world into res cogitans and res extensa, he puts the former over the latter, allowing him to guarantee his existence only through thinking. G. E. Moore tries to refute this by stating that he can hold his two hands up, yet he only arrives at the conclusion that his two hands exist, not that the outside world does. Kant proposes that everything is in one’s imagination, yet believes that the self could only be so by differentiating itself from the rest of the external objects. Nevertheless, Descartes proposes that all of this could just be a figment of one’s own imagination, or the work of an evil demon. Therefore, even though one may constantly have the experience of an outside world, there is no actual way to assure this beyond any doubt.
Reference List
Descartes, R. (2008). Discourse on the Method of Rightly Conducting One’s Reason and of Seeking Truth in the Sciences. Retrieved from http://www.gutenberg.org/files/59/59-h/59-h.htm#part4
Kant, I. (1998). Critique of Pure Reason. (Paul Guyer & Allen W. Wood, Trans.). Cambridge: Cambridge University Press.
Moore, G.E. (1993). “Proof of an External World.” In Thomas Baldwin (Ed.), G.E. Moore: Selected Writings (pp. 147-170). New York: Routledge.
