In "Appearance and Reality," Bertrand Russell asks the question: "Is there any knowledge in the world which is so certain no reasonable man could doubt it?" Hume and Descartes would have certainly had different thoughts on the matter. By looking at the ideas put forth by both Descartes and Hume we can gain a better understanding of how humans process knowledge.
Descartes’ dream conjecture questions the human ability to distinguish falsities from reality. In essences’, the doubt that Russell speaks of in his statement. The premise of his reasoning is to ask the question, “How can be distinguish when we are awake from when we are dreaming?”(Cottington, 1984).
The premise is that when we are dreaming, these dreams seem to be our reality at that moment. If this is true how do we know when we are truly awake? After all some dreams are very vivid and lifelike. Descartes states, "For all I know, I might now be dreaming."(Cottington, 1984) . Descartes is unable to establish a test to determine the difference, therefore no real way to determine the truth. His reasoning states that our awareness when awake of dreaming is very similar phenomenologically(Cottington, 1984).
The origins of the ideas help Descartes classify them. Some ideas are innate, some are adventitious, and some are imagined("Descartes' proof for," 2012). The truth comes from their own innate nature. Those perceived by the senses are considered adventitious, and those imagined are of the thinker’s invention("Descartes' proof for," 2012). By classifying ideas, Descartes must determine the reason why he thinks what he does. He determines that nature teaches him, and that ideas appear independently.
David Hume also had his own ideas about how humans perceive reality. Hume proposes that there are two different types of reality, one that relies on perceptions and memory and another that is what the mind determines is reality. The mind creates a perception based on the judgments it makes. However there are flaws with how the mind perceives things because it often may be missing key elements to help make these judgments. The things a person senses impacts these judgments.
I tend to agree more with Hume’s theory because I find that his theory seems more scientifically plausible than that of Descartes. It seems reasonable that things we experience as a result of our senses would impact our thought process and help construct a mental image within our subconscious to help us determine if something is real or not.
In conclusion, Descartes’ theory may never be solved. Known for his reasoning, Descartes was able to solve many of life’s most pressing questions by applying reasoning to formulate very logic answers. Hume’s theory does seem like it might be able to be explained scientifically by measuring brain activity and relating it to perceptions of reality. Russell’s statement stirs a philosophical debate over the perception of reality within ourselves and in society.
References
Cottingham, John, Robert Stoothoff, Dugald Murdoch, and (for vol. 3) Anthony Kenny, eds. and trans. 1984. The Philosophical Writings of Descartes, vols. 1–3. Cambridge: Cambridge University Press.
Descartes' proof for the existence of god. (2012). Retrieved from http://oregonstate.edu/instruct/phl302/philosophers/descartes-god.html
Nolan, L. (2011, April 12). Descartes' ontological argument. Retrieved from http://plato.stanford.edu/entries/descartes-ontological/
