.: G.E. Moore and Norman Malcolm on Certainty

Sunday 13 June 2021

G.E. Moore and Norman Malcolm on Certainty

The philosophers Bertrand Russell (1872–1970) and A.J. Ayer (1910–1989) once argued — along with many others — that no empirical statement could ever be certain. As a consequence of that position, Russell particularly targeted the use of the word “certain” in ordinary language.

The American philosopher Norman Malcolm (1911–1990) put what he called “the philosopher’s position” in this way:

“[I]t never has been and never will be right, for any person to say ‘I know for certain that p’, where p is a material-thing statement, is that he regards that form of speech as improper. He regards it as improper in just the same way that the sentence ‘I see something which is totally invisible,’ is improper… in the sense in which every self-contradictory expression is improper.”

Certainly at first glance it does not seem that the sentence

“I know for certain that I have two hands.”

is linguistically “improper” and/or indeed “self-contradictory”. The sentence

“I see something which is totally invisible.”

on the other hand, can be seen as linguistically improper and/or self-contradictory. That said, it’s not even clear that the word “improper” should be used about the above. After all, I understand it. Why not simply say, instead, that it’s false or that it does indeed say something which is self-contradictory. It’s just odd (or even pompous) to argue that it’s linguistically improper (or a “misuse” of language). Indeed even Noam Chomsky’s well-known sentence

“Colorless green ideas sleep furiously.”

can be deemed to be linguistically proper in that it’s grammatically correct. What’s more, perhaps Ludwig Wittgenstein (1889–1951) might have argued that there could be a language-game in which the sentence above is perfectly proper. Thus the same may go for “I see something which is totally invisible”. That sentence can still be said to be (simply) false and/or self-contradictory.

Again, the sentence

“I know for certain that I have two hands.”

is only improper if one knows about — and is committed to — the philosophical position which renders it improper and/or self-contradictory. Yet ordinary language isn’t really (or at least always) a philosophical language. So why should the utterer have prior knowledge of Bertrand Russell’s — or any other philosopher’s — philosophical position before he/she can say something about his/her hands? Indeed what if another philosopher says something different about that very same sentence? For that matter, what if a philosopher sees it as perfectly proper — as G.E. Moore himself did?

We can’t escape the fact that even if this sentence is improper and/or self-contradictory, then it is so only according to a prior philosophical theory which we may have no knowledge of. And even if we have knowledge of — or a commitment to — it, then we can still separate it from our ordinary-language locutions and commitments. Yet Bertrand Russell and A.J. Ayer suggested that we use the language of philosophers — and not ordinary language — when we’re tempted to say things like “I know for certain that I have two hands”. They argued (at least at one point in their careers) that only in logic and mathematics can statements be certain. (No empirical statement can ever be certain.) Thus one must conclude that anything we say about the two hands in front of us can never be certain.

G.E. Moore on Certainty

As a riposte to all that, Norman Malcolm quotes the English philosopher G.E. Moore (1873–1958) in this way:

“‘It is a proper way of speaking to say that we know for certain that there are several chairs in this room, and it would be an improper way of speaking to say that we only believe it, or that it is only highly probable!’”

“The philosopher” says that Moore’s way of speaking is “improper” and Moore (who was a philosopher) says that the philosopher’s way of speaking is improper. Moore’s way is improper, according to the philosopher, because we can never be certain about the empirical matter of there being two chairs in a room. The philosopher’s way is improper, according to Moore, because he’s using the word “certain” in its strictly logical sense — i.e., not how it’s used in ordinary language. Yet both the philosopher and Moore are talking about the correctness or otherwise of “linguistic statements”; not about the truth or falsehood of an empirical fact. According to Moore, “when we sat in a room seeing and touching chairs” it would simply be wrong (according to the dictates or ordinary language — if such things even exist) to say that

“we believed there were chairs but did not know it for certain, or that it was only highly probable that there were chairs”.

Quite simply, phrases like “highly probable” aren’t (often?) used in ordinary language. Or, if they are, then they aren’t used in contexts like this. Instead they’re used in sentences such as this:

"It is highly probable that the Loch Ness monster does not exist."

Not in sentences like this:

“It is highly probable that these chairs in front of me exist.”

So we can now say:

“I believe that the Loch Ness monster exists.”

However, we can’t say:

“I believe that these chairs in front of me exist.”

Similarly, many people would say that they aren’t certain that God exists; though they are certain that the two chairs in front of them exist. Another way to put this is as Moore did. He argued that if a child were to say (not that he would) “that it was ‘highly probable’ that there were chairs there”, then “we should smile, and correct his language”.

We can now ask, then, whether or not all these disagreements are really just about language, semantics or language use; rather than being about whether or not the chairs really do exist or whether we can be certain that they exist.

So doesn’t all that raise questions against Moore’s thesis?

What Norman Malcolm wrote next suggests that this isn’t just a question of language or semantics. It is, in fact, about what is expressed by “empirical statements”. Malcolm continued:

“Moore’s reply constitutes a refutation of the philosophical statements that we can never have certain knowledge of material-thing statements… and so shows us that Ayer is wrong when he says that ‘The notion of certainty does not apply to propositions of this kind.’…”

So Moore wasn’t just arguing that we’re allowed to use the word “certain” in “material-thing statements” (i.e., not just in logic and maths). He was arguing that we’re certain that what those statements claim is in fact the case. In this case, we’re certain that the chairs in front of us exist. After all, “material-thing statements” are about… well, material things. And Moore argued that we’re certain about the existence of (certain) material things such as chairs and our hands. Indeed what would be the point of being able to use the word “certain” if we weren’t (really) certain about material things? (Similarly with the word “know”.)

Having said that Moore’s position isn’t just a question of correct usage or semantics, Malcolm does then go on to make a distinction between the phrase

“I know for certain…”

as it’s used in — or about — a priori statements; and as it’s used in — or about — empirical statements. In each case, the word has a different (to use Malcolm’s word) “sense”. Malcolm wrote:

“The truth is, not that the phrase ‘I know for certain’ has no proper application to empirical statements, but that the sense which it has in its application to empirical statements is different from the sense which it has in its application to a priori statements.”

We’ll need to know what sense the word “certain” (or the phrase “I know for certain”) has when applied to an empirical statement. It clearly can’t have the sense that “the negative of it is self-contradictory”. That sense, then, must be that if we can see and touch our hands or the chairs in front of us, then we have the right to be certain that such things exist. The “negative” of such empirical statements will indeed not be self-contradictory. That’s because these statements aren’t supposed to be a priori or logical in nature — i.e., they don’t even open up the possibility of any contradictions or self-contradictions. However, couldn’t we say that it’s indeed self-contradictory to claim the following? -

“I can see and feel these chairs in front of me but I don’t know for certain that they exist.”

At least according to the dictates of ordinary language that sentence is contradictory. In this example, then, it wouldn’t (only) be a question of “correcting the language” of the person who uttered the above. In other words, if you can see, feel and kick the chair in front of you, then what more do you want or need? You can’t have logical or a priori certainty about this claim because it isn’t a logical or an a priori statement. So let us, Wittgenstein might have said, keep our language-games apart. And by keeping them apart, we can also stop all this silly fuss and bother about certainty or the correct use of the word “certainty”.