Discussion: How do we know anything?
How do we know the world around us? Epistemology is the branch of philosophy devoted to questions of human knowledge.
One of the most important figures in the development of epistemology is the French philosopher Rene Descartes (1596-1650). He observed that a particularly vivid dream is virtually indistinguishable from reality. We realize that we have been dreaming only upon waking. If I don't know that I'm dreaming when I'm dreaming, Descartes asked, how do I know that I'm not dreaming now? In other words, given that I can be completely mistaken about the nature of reality during a vivid dream, how can I be certain that I'm correct about the nature of reality when I'm awake?
This line of thought led Descartes to formulate his famous "Evil Demon" or "Evil Genius" problem, in which he wonders if some type of evil entity has deceived him about everything. What if nothing exists, and everything that we see around us is an elaborate illusion? Descartes went so far as to wonder if he himself existed, but he concluded that he must, because even if everything else were an illusion, he must exist because he can think about it--hence his famous dictum "Cogito ergo sum" or "I think, therefore I am."
A colorful modern formulation of the problem Descartes posed is the Brain-in-a-Vat Problem, in which we imagine that you have been in a horrible accident in which your body has been irreparably destroyed. Your brain, however, is just fine, and somehow a group of unscrupulous scientists acquire your brain and erase all your previous memories--much as one might clear a hard-drive. Then, they put your brain in a vat and hook it up to a machine that perfectly simulates a false reality. You experience babyhood and childhood--you grow up, fall in love, get your heart broken, marry, have children, get jobs, and lose jobs. All these experiences are mere illusions, however. You're really just a brain in a vat.
Various solutions have been proposed to the Brain-in-a-Vat Problem, but none has ever gained widespread acceptance among philosophers. To this day, it is considered one of the most formidable epistemological puzzles.
Read about "Rene Descartes."
Read "Existential Comics: Descartes's Demon."
Read "Evil Genius Doubt."
Read "The Brain-in-a-Vat Argument."
Answer the following questionsin One page:
1. What role does dreaming play in the development of Descartes's radical skepticism?
2. Why does Descartes believe that he can know for certain that he himself exists?
3. What is your opinion of the Brain-in-a-Vat Problem? Do you think it can ever be solved?