It's all about the deep questions.
Category Archives: Epistemology
Closing the Loopholes
In this post, I’ll go through some limitations of the argument, and how the argument may even be modified slightly in order to reach a stronger conclusion. First of all, it is clear that no skeptic conclusion can conclude that all knowledge is impossible. One example of infallible knowledge that everyone can have, famously stated by Descartes, is that he himself exists. Simply thinking about the question implies one exists to do the thinking, which directly leads into the famous quote, “I think therefore I am.” Most skeptical theses, therefore, argue against the possibility of knowledge about the external world (although recent psychological studies point to the fact that we know far less about our “internal” world than we once thought). Some further restrictions must be made to this skeptical thesis, however. Certain trivial analytic statements (statements true simply by virtue of the concepts involved) certainly cannot be included in a skeptical thesis. It is pretty easy to know, for example, that if there are bachelors, than they must all be unmarried.
So what does it mean for “someone to know nothing about the external world”? Three cases of knowledge are under the umbrella of this statement
- Any case of someone’s knowing something which entails the existence of some concrete entity outside his own mind. (Example: Someone knowing that many bachelor’s are happy since that entails the existence of at least one bachelor.)
- Any case of someone’s knowing something which entails that some concrete entity, such that it is not an anlytic or logical truth that it does not exist (outside the person’s mind), does not exist. (Example: Someone knowing that there are no flying pigs exist.)
- Any case of someone’s knowing something which entails a truth about a concrete entity, which is not an analytic or logical truth. (Example: if dolphins exist, then they are rainbow.)
That is a pretty strong skeptical position!
There are a couple of exotic cases that fall under these bullet points that do not seem to be compellingly addressed by our argument, however. Consider someone who believes that there actually is an evil scientists out there deceiving people. One thing he does know is that if there is an evil scientist messing with his brain, then it is not the case that that scientist is deceiving him into believing falsely that an evil scientist exists. Because if there were such an evil scientist, then it would be true that he existed! Therefore, according to this argument, he might as well know that an evil scientist exists (this argument doesn’t counter that belief). This suggests the use of contrast cases. If one knows that an evil scientist exists, then he would have to know that when he was born he wasn’t filled with drugs or chemicals that make him constantly fall into error about external matters, so that his beliefs are only randomly related to the external world. Read more of this post
My favorite debates in epistemology have always been the debates for and against skepticism, and the “brain in the vat” thought experiment has always been a classic in the field. Here, I will present the argument and give a few preliminary justifications. Later, another posts will consider the objections and counter-objections to the argument.
1. If one knows some fact about the external world, p, then one can or could know that he at least believes that p and, furthermore, that there is no evil scientist, a being other than himself, who is deceiving him into falsely believing that p.
2. In respect of anything which might be known or believed about the external world, say p, no one can our could know that he at least believes that p and that there is no evil scientist, a being other than himself, who is deceiving him into falsely believing that p.
3. In respect of anything which might be known or believed about the external world, say, that p, no one ever knows that p.
This premise relies on “the assumption of reasoning” or the fact that knowledge is closed under entailment. Basically, if one knows that p, and it is true that p entails q, then one can or could know that q. So, if someone knows some fact p, then that entails that he can or could know that he is not being falsely deceived into believing that p. Lastly, the first part of the “then” clause relies on the almost unanimously agreed fact that to know that p, it is necessary to believe that p. It is the second part of the “then” clause which cannot be satisfied. As a whole, I see this premise to really be uncontroversial. After all, how could it be false?
This comes to the classic “brain in the vat” scenario. Intuitively, one can never know that one is not a brain in a vat being poked by electrodes to falsely believe in various propositions. This premise has, however, been objected to, and we will look into those objections later. The first time I heard this premise though, I thought it was pretty obvious.