Unger

Paper on Peter Unger’s “An Argument for Skepticism”

Peter Unger is one of the more contemporary advocates of philosophical skepticism. In this article he presents a positive argument for skepticism, which he claims is: “that nobody ever knows anything to be so”. Unger argues that knowledge requires certainty, so that one can hardly know anything, or at least not with being absolutely sure about it.

To be more precise, Unger´s argument runs as follows:

(1) If someone knows something to be so, then it is all right for the person to be absolutely certain that it is so.

(2) It is never all right for anyone to be absolutely certain that anything is so.

(3) Nobody ever knows that anything is so.

The argument is valid, so there has to be something wrong with the premises to make it unsound to refute Unger´s argument. But let us first have a look how he explains his argument. Unger says that there is an analytic connection between knowing and being certain, which is evidenced in how we use the word “know”. He poses questions like “How can you be certain of that?” and using examples like “He knew it was raining but wasn’t certain it was.” Being absolutely certain of something involves one having a pessimistic attitude concerning of whether that circumstance is like it is: one must have an attitude regarding new information, evidence or experience which would cause you reconsidering your meaning and thinking in this case. In other words: in order to be absolutely certain that “x”, we must be willing to not consider any new information we might achieve that would show that “x” might be proven as false. But after all, one cannot be certain of a proposition at one point in time, only to become uncertain of it at a later point in time. For example because of new evidence one obtains, or because one has had second thoughts about the reasoning on which one had

become certain of the proposition, or because doubts have arisen about the trustworthiness of one’s informant....