G. E. Moore’s “Four Forms of Scepticism” (selection)

[I got this paper from an epistemology anthology, and it appears to be a selection rather than the whole thing.]

The evil demon argument says that it is a logical possibility that a malicious demon exists and is causing us to perceive objects, and therefore we cannot trust our sense perceptions. Since we cannot be certain that such a demon doesn’t exist, we cannot know anything that we receive through our senses. Russell’s claim isn’t that the demon is a physical possibility, nor is he claiming that the demon actually exists. Instead, his claim is that the evil demon is a logical possibility. What does he mean by this?

Moore thinks that understanding this will show us the difference between Russell and him.

The three questions that have to be answered are: (1) What does it mean that this is a logical possibility? (2) Is it true that it is logically possible? (3) If it is true, then is it true that I cannot be certain that a perception isn’t caused by an evil demon?

Moore can think of three things that might be meant by saying that such a demon is a logical possibility. First, you might say that the idea doesn’t involve a logical contradiction. But this isn’t what Russell means, because even if the idea of such a demon doesn’t involve a logical contradiction, then I can still know it to be false.

Second, Russell might mean that the idea of an evil demon doesn’t contradict what I already know. But that is begging the question, because the very thing I’m claiming to know is that my perception is caused by the external world, not the malicious demon, and surely that contradicts the idea of the malicious demon.

Third, and this is most likely what Russell means, is that the idea of an evil demon doesn’t contradict anything I know *immediately* or anything that is derived from immediate knowledge. Moore admits that he doesn’t *immediately* know that, for example, his perception of a pencil isn’t caused by the evil demon, that a certain person is conscious, or anything else logically incompatible with being caused by a evil demon. (And Moore says that some philosophers will disagree with him and Russell, and assert that one can know these things immediately.) But, where he does differ from Russell is that Moore believes that even if we don’t know something immediately  we can still be certain of it. “Where is Russell’s argument against this?” Moore asks.

To the best of Moore’s knowledge, Russell bases the idea that I cannot be certain of what I don’t know immeidately or of what I derive from immediate knowledge upon two ideas: (1) that what cannot be known immediately or derived from immediate knowledge must be based upon analogical or inductive arguments; and (2) we cannot be certain of what we know through analogical or inductive arguments. Moore thinks the first is true, but he doesn’t believe the second assumption. He thinks we can be certain of things known through analogical or inductive arguments.

But Moore really wants to ask Russell the following: Russell’s idea that we cannot be certain of beliefs such as “The other person is conscious” or “I hold a pencil in my hand” is based upon four assumptions: (1) That I don’t know such things immediately; (2) that I don’t deduce knowledge of them from things I know immediately; if both of these are true, then (3) I must know these things from analogical or inductive arguments; and (4) we cannot be certain of what we know from analogical or inductive arguments. So, Moore wants to ask Russell, are you more certain of any of these assumptions than you are that you have a pencil in your hand or that a certain person is conscious?

Moore is more certain that he is holding a pencil in his hand than he is of any of these assumptions, much less all of them, even though he agrees that assumptions 1-3 are true.

Moore believes that it is not rational to be more certain of all of those assumptions than you are that you hold a pencil in your hand or that another person is conscious.

 

5 Key Points

1. Russell believes that you cannot be certain of things that are based upon analogical or inductive arguments.
2. Moore thinks you can be certain of things based upon analogical or inductive arguments.
3. Russell and Moore think that things you don’t immediately know or base upon immediate knowledge can only be known through analogical or inductive arguments.
4. For an argument to be objectively convincing, then you must be more certain of all the premises and assumptions than you are of the negation of the conclusion.
5. Moore thinks memory and much of one’s knowledge about oneself is immediate knowledge.

Tags: Evil Demon Argument, Moore, Philosophy, Russell, scepticism, skepticism