This is a paper I just wrote for a class in epistemology. Basically, I don't like reading G.E. Moore a lot (read him yourself and find out why...) so I tried to attack his position. Judge for yourself how successful I am

In his essay A Defense of Common Sense, G.E. Moore attempts to present a philosophical defense for the common sense view that things do, in fact, exist outside our minds. I do not believe that he succeeds in this attempt. It seems that he neither presents a viable refutation of skepticism or a convincing philosophical defense of common sense. My reason for believing this may appear, at first, to be merely a poor choice of words on Moore’s part. But, I will argue, that this choice of words has dire consequences for his larger argument. In particular, I would like to focus on Moore’s use of the phrase “in my opinion” (Moore 53 and 54) and how this phrase presents problems for his claims about certain knowledge.

But before I attempt to critique Moore’s argument I think it would be helpful to quickly summarize his relevant points. His short essay is structured into two points (the second of which follows, according to Moore, from the first). His first point involves:

…a whole long list of propositions, which may seem, at first sight, such obvious truisms as not to be worth stating: they are, in fact, a set of propositions, every one of which (in my own opinion) I know, with certainty… (Moore 53).

This list of (‘certain’) truisms includes propositions like: “there exists at present a living human body which is my (i.e. Moore’s) body” and that “there have, at every moment since (this body’s) birth, been large numbers of other human bodies…” (Moore 53). The list is (as Moore tells us) long but its content is not immediately relevant to the general criticism I wish to make of his argument. His second point is merely that “each of us … has frequently known, with regard to (our bodies) everything which… I was claiming to know about myself or my body…” (Moore 54).

I will quickly schematize Moore’s argument before I begin my critique:

1. He knows a certain number of propositions with certainty (in his opinion)

2. We (humans in general) know (with certainty) the various propositions he listed in 1 (also in his opinion).

I’ve italicized what I think is the most important (and dangerous) part of Moore’s argument; that both these claims are Moore’s own stated opinions. At first glance, there seems to be a problem here. Moore states both that these claims are known “with certainty” (Moore 53) and that they are his “own opinions” (Moore 53). I’ll make the problem more explicit: there seems to be a contradiction in terms between ‘opinion’ and ‘certainty’. The term ‘opinion’ is commonly used to talk about things of which we are not absolutely certain but that are relative to our own particular tastes (my opinion that British food is bland is, for instance, not an absolute certainty, but one that is relative to my tastes). In contrast, the terms ‘certainty’ or ‘certain knowledge’ are commonly seen as non-relative, even ‘absolute’ (in the common view two plus two equals four is not something that varies from person to person). We tend to strongly distinguish between our personal opinions and what is certain. It seems, however, that Moore fails to make this distinction.

However, Moore may be rescued from this seeming contradiction if he redefines either (or both) of the terms. To examine this possible avenue of escape, I will attempt to define the terms ‘opinion’ and ‘certain knowledge’ based on Moore’s usage in his essay.

Moore states:

I have had expectations with regard to the future, and many beliefs of other kinds, both true and false; I have thought of imaginary things and persons and incidents, in the reality of which I did not believe (Moore 54).

Though this is not explicitly a definition of opinion I believe it is the closest thing to a direct statement about opinion within the essay. Without an explicit definition of terms to the contrary, I do not think it unreasonable to attribute the common definition of opinion to Moore (who is, after all, a Common Sense philosopher). According to the common definition, ‘opinion’ can fall into the category of expectations with regard to the future (the opinion that it will rain tomorrow, for instance). It can also reasonably be considered as ‘thinking of imaginary things’ (i.e. the opinion someone might have that they would be a better suited for the job of Prime Minister than Jean Chretien). Based on this definition, opinion can be indeterminate (in the case of prediction or conjecture), true or false. It also follows from this definition that we can have opinions of things that exist only in our minds.

From this definition I argue that not only can our opinions be true or false relative to our own minds but that all our opinions are true and false only within our minds. For example: my opinion that I enjoy the colour red is true only within my own mind. The way I go about verifying a particular opinion is not to go out into the world (external to my mind) and look around for evidence that my opinion is ‘true’, rather I ‘look’ into my mind and ask myself if I enjoy the colour red. If I answer yes, then my opinion is true. It is similar in all matters of opinion (which are, in common parlance, distinct from matters of certainty, or knowledge).

This brings us to Moore’s definition of certainty, or certain knowledge. Though I’ve already quoted it above, the following passage is helpful in reconstructing what certainty might mean for Moore (as he never directly tells us in his short essay). He states that his first point is

…a whole long list of propositions, which may seem, at first sight, such obvious truisms as not to be worth stating: they are, in fact, a set of propositions, every one of which (in my own opinion) I know, with certainty, to be true (Moore 53).

It is important to keep in mind that the certain knowledge Moore is claiming to possess is not directly of the external world. Which is to say that: Moore is claiming that he knows that a certain long list of propositions (which pertain to the existence of external things) is true. Thus, Moore’s claims about certain knowledge are not about the external world, nor are they about propositions about the external world, but about the truth-value of those propositions. Thus it seems that Moore’s position is that certain knowledge of a proposition just is knowledge of its truth-value.

So, now that we have our definitions solidified, I think we should return to the apparent paradox at the root of my critique: How is it that Moore can at once claim to have certain knowledge of something, yet state that it is certain knowledge in his own opinion?

Given that certain knowledge of a proposition just is knowledge of its truth-value, I think that Moore can escape the paradox that I set up above. However, his escape leads him from the pan into the fire. If we accept the definitions given above Moore is lead into the following position:

1. Opinions are true relatively to the mind of the one who holds the opinion.

2. Certain knowledge is knowledge of a proposition’s truth-value.

3. In my opinion I know with certainty that: ‘The external world exists’

4. Thus: I know that my opinion that the external world is true.

5. Therefore: I know that I hold the opinion that the external world is true.

So, in escaping the definitional paradox (between certainty and opinion) I set up above, Moore is led to the conclusion that he does not, in fact, know that the external world exists. He merely knows that he is of the opinion that it exists.

My line of argument may be seen as philosophical nitpicking, but I think it hints at the problems that underlie Moore’s common sense project as a whole. It shows that the common sense attitude, if taken as a philosophical stance, can be shaky at best as a ground for certainty. Even without the qualifier “in my own opinion” he simply cannot escape the problem of solipsism by appeal to common sense. Had he taken a more assertive approach, and declared outright that he “knew with absolute certainty that the external world existed independently of our own minds”, we (that is, the philosophical community) would have rightly questioned him: “And how precisely did you manage to do that?” The tactic that he takes (simply presenting the common sense view) does not (in my ‘opinion’ at least) pose serious problems for any solipsist’s objections to the existence of the world. Rather than a challenging philosophical stance, Moore is taking the easy road (by philosophical standards) and simply saying that the question is moot: according to Moore we all do, indeed, know that the world is there.

While it may be that no one ‘seriously’ (that is, in their everyday lives) doubts that the external world exists, the philosophical concern seems to be with providing a solid proof that the world does exist. Such a proof would, theoretically, be able to convince an absolute solipsist that the external world does exist. As I have stated, I do not think that Moore’s argument (even without the opinion qualifier) is able to do so. I think the conversation between our un-qualified Moore and the absolute skeptic would go something like this:

Moore: The world exists independent of our minds. Skeptic: No, it does not. Moore: Yes, it does. (ad infinitum)

Though it may be flippant, I think the above imaginary conversation illustrates better than argument what I see as the flaw in Moore. Other than presenting common sense, Moore really has no philosophical ground for his knowledge claims. And mere reliance on common sense is patently not a strong ground on which to build claims of certainty. If it were, epistemology would never have become a distinct branch of philosophy.

The article I'm referring to is:

Moore, G.E., “A Defense of Common Sense,” pp. 53-54 in The Theory of Knowledge: Second Edition, edited by Louis P. Pojman (Wadsworth Publishing Co., London, 1999).

Read some Artaud, it will make you feel better.

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