G. E. Moore's, "Proof of an External World"

Dialogue about G. E. Moore's famous proof, using the following passages from his article, "Proof of an External World":

"proof of the existence of things outside of us... I can now give a large number of different proofs [of the existence of things outside of us], each of which is a perfectly rigorous proof... I can prove now, for instance, that two human hands exist. How? By holding up my two hands, and saying, as I make a certain gesture with the right hand, "Here is one hand", and adding, as I make a certain gesture with the left, "and here is another"

"the proof which I gave was a perfectly rigorous one; and... it is perhaps impossible to give a better or more rigorous proof of anything whatever.... (1)... the premiss which I adduced as proof of the conclusion was different from the conclusion I adduced it to prove; (2)... the premiss which I adduced was something which I knew to be the case, and not merely something which I believed but which was by no means certain, or something which, though in fact true, I did not know to be so; and (3)... the conclusion did really follow from the premiss."

Category:

Education

Tags:

• G.
• E.
• Moore
• proof
• external
• world
• philosophy
• epistemology
• knowledge
• hands
• PhilosophyAnimation
• xtranormal

[MirageScience]

A mind-independent reality or in other words a world/universe that exists independent of consciousness is NON-COGNITIVE. We can't even conceive on one. Go ahead and try to conceive of one, then ask yourself how you are conceiving of it. You will see that every world you can even conceive of contains your own mind. I think that a pretty good damn reason to not even try to give a proof of an external world. I mean how can you prove that something exists if it's inconceivable?

[PhilosophyAnimation]

@MirageScience You're thinking like Berkeley and Schopenhauer, which I disagree with. When you conceive of a world, you don't have to conceive that your conception is in that world, present at the very situation you are conceiving. Instead you can just conceive the world as being a certain way. For instance, a Big Bang without any mind. If it seems like there is a mind conceiving it, well, there is, but it's you here and now, not some person in the hypothetical scenario.

[PhilosophyAnimation]

In his paper, "Certainty", he does a tad better than hand-waving. He asks: “It is logically possible both that you should be having all the sensory experiences you are having, and also that you should be remembering what you do remember, and yet should be dreaming?” His answer: if it is possible, then one cannot possibly know for certain that one is not dreaming. Yet he doesn't see any good reason to think that it is possible! And being certain only requires ruling out possible alternatives.

[willardsheen1]

Thanks for the replies. The objection to the second condition seems quite powerful. Ultimately Moore seems to be saying: I know the external world is real because I know it is. Yet suppose there is a mystic who knows that the external world doesn't exist, knows it's a dream. He holds up one hand then another, says: Here is one imaginary hand, and here is another etc. This proof is as valid as Moore's, yet arrives at the opposite conclusion. So how valuable can Moore's proof be?

[PhilosophyAnimation]

@willardsheen1 The mystic's argument would be invalid. For the existence of those two imaginary hands would not imply that there is no external world. (Similarly, if Santa Claus and the Tooth Fairy are just imaginary, it doesn't follow that the external world is imaginary as well.)

[willardsheen1]

Could anyone explain why Moore talks of holding up two hands? Wouldn't his argument be just as valid if he used only one? Is the proof altered somehow by using two, and if so, how? If not, why did he talk of two hands?

Good video by the way.

[PhilosophyAnimation]

@willardsheen1 Good question. Knowing that there is one hand in the external world is all he'd need to defeat the skeptic. With that said, it might be slightly harder to know that there are two human hands, partly because of the commitment to their being human, partly because counting to two might be a tiny bit harder than counting to one, and partly because you'd have to rule out the option that you're having double vision of a single hand. Maybe he was just being cocky, trying to show off.

[willardsheen1]

@PhilosophyAnimation I take your point. A real hand is proof enough that an external world exists, whereas a phoney hand only proves the hand doesn't exist. Thanks for that.

[davvydavy]

I love how at the end she totally gives him the "talk to the hand"

[insacredflames]

@willardsheen1 It makes no difference whether he uses one hand or two.