I. Background

A. Types of Skepticism

 

Global Skepticism is the view that we don't know anything, or, in some formulations, the view that we can't know anything. Skepticism can vary in its extent. What I just described is total skepticism (or universal skepticism): No one knows anything at all. Hardly anyone accepts this.

 

Local Skepticism is the view that we can’t, or don’t, know anything about some specific topic.

Eg., some would say that we can know about our own thoughts and feelings, but can't know anything beyond that. Some think foundationalism leads to this sort of local skepticism: we can know the things classical foundationalists take as basic, but we can't get any knowledge beyond that. This is skepticism about the external world. It is the most widely discussed kind of skepticism. And, even though it counts as local skepticism, it is still broad and far reaching. Some people are skeptics about the future, others are skeptics about other minds, and so on.

 

We are all skeptics about some topics. That is, we think that there are truths we don't know. I think that there is much about the distant past that we don't know, and, moreover, will never know. But this isn't a very interesting version of skepticism.

We’ll mainly think about external world skepticism.

 

B. A Distinction

There's an important distinction to keep in mind. Suppose you think that we can't have knowledge about ethical matters, we can't know what's right and wrong. Version 1: there are ethical truths, but we can't know what they are. Version 2: there are no ethical truths. People sometimes run these things together. We're mainly interested in Version 1. It holds that there are truths in some domain, but we can't or don't know what they are. Version 2 might be described as skepticism (or doubt) about the existence of ethical truths. It’s like “skepticism” about the existence of life on other planets. This is not a view about any epistemological issue. If there are no facts of a certain sort, then, obviously, we can’t know the facts of that sort. Another example: aesthetic facts - is there a truth about whether one object is (really) beautiful. The debate about this is not a debate about an epistemological matter. It’s about a “metaphysical” or “ontological” matter. If we conclude that there are truths, then we can go on to think about whether we can know what they are. But if we conclude that there are no such facts, then there’s no meaningful issue about whether there can be knowledge.

 

So skepticism as we are discussing it says that there are facts, or truths, about a topic, but we can’t know what they are.

 

C. Refuting Skepticism and Defeating Skeptics

We will soon look at some arguments for skeptical conclusions. You can view skepticism as a difficult and challenging intellectual problem arising from the fact that these arguments are difficult to refute. The main question then is what the most reasonable attitude to take toward these arguments is.

 

A different approach is more “dialectical”. You can view skepticism as a kind of contest: you claim to know things and skeptics claim that you don’t. You then see whether one side can persuade the other side. This often degenerates into frustration. Non-skeptics accuse skeptics of a kind of inconsistency: they say that we don’t know anything, then they give arguments that have premises and they seem to assume that they do know these premises. Some examples of dialectical disputes:

 

1) Suppose a skeptic says, “Sometimes you make mistakes, so it’s possible that you always are making a mistake.” Some skeptical conclusion is then drawn from this. You might reply “How do you know that you sometimes make mistakes?” This is supposed to bad for the skeptics. Don’t they have to know that their premises are true? But they claim they don’t. However, this really isn’t much of threat to skepticism. You agree with the premise, (right?). It is part of the Standard View. So the interesting question is whether the conclusion follows from the premise. (It doesn’t.)

 

2) Sometimes the question is whether one can live the life of a skeptic. “If you think that you don’t know that there are any other people, why do you write articles and give lectures about skepticism?” Why do they resist walking in front of buses? Again, this issue is potentially interesting, but best left aside. Skeptics don’t deny that they believe anything. They just deny that we have knowledge.

 

3) If you try to give an argument to a skeptic to show that we do know something, then, whatever argument you give, a skeptic can ask why you accept your premise and can deny it. Skeptics can continually reject any assumption or premise that a non-skeptic puts forward. They can be intransigent and uncooperative. That can be annoying. But there’s no reason to care about that.

Our issue is not dialectical. It is: what should we think about these skeptical arguments? Is there something wrong with them?

 

II. One Common Argument for Skepticism

 

See section IIB in the text.

Important conclusion: skeptics are denying that we have justification of the sort need for knowledge; they are not saying that our beliefs are uniformly false.

 

III. Arguments for Skepticism

Review the four arguments for skepticism. Get initial reaction.

 

IV. Responses

A. The Moorean response: the argument must have a false premise.

 

B. Fallibilism: we now have something of a basis for thinking that a key premise of each argument is false.

How strong is the case for fallibilism? Two considerations are given in the book, p. 123. One: after asking about knowledge, asking about certainty seems to be asking for more; Two: a practical consideration. What do these really amount to? Are they convincing? Does saying, “I know but I’m not sure” really make any sense?

 

Here’s a thought. When you say that you know something, a common inference, perhaps an “implicature” is that the hearer need not check on the topic. This makes sense, “I know that I locked the door, but I’ll check since it’ll make me (you) feel better.” The implicature can be cancelled.

 

C. If-then sentences and necessity. This may be the most confusing point in this section. See p. 124.

 

A related idea: The skeptical scenarios show that it’s possible that you don’t know. It doesn’t follow that you don’t know.

 

V. Three claims about skepticism

The following are the central claims of the chapter:

 

1) If the standards for knowledge are very high - if knowledge does require certainty, impossibility of error, etc. - then we don’t know anything.

 

2) The first three of the four arguments for skepticism in the text all depend, in one way or another, on the claim that knowledge does have very high standards.

 

3) Knowledge does not have very high standards.

These claims are stated in decreasing order of confidence.

 

An additional claim, not in the chapter:

 

4) What knowledge does require is what we can call “the criminal standard” - evidence beyond all reasonable doubt.