Critically Evaluate Moore's Proof of the External World

Q: Critically evaluate Moore's proof of the external world.

A: This being a critical evaluation, we will follow the traditional Indian format for such an undertaking in that we state Moore's position (purva-paksha) followed by a refutation of his position (khandan) and conclude with stating our position (siddhant). There are a two points to be bought to attention in this regard:

a. the purva-paksha includes Ms. Alice Ambrose's views in support of Moore's position

b. since Moore is a realist, a siddhant would possibly be an idealist position and for this we merely state Berkeley's viewpoint in brief in this regard

Purva-paksha

Moore's position

Moore attempts at giving a proof of an external world for which he starts with stating that Kant was the first person who thought that it was scandalous that such a proof had not been given up to his time. Moore then states that, though Kant had said he had the only possible proof for this, he would try to attempt another one. His first task then is to make clear certain terms which seem to him ambiguous. Among these, the major ones are:

a. "things to be met with in space" (henceforth called TMWS)

b. "things to be presented in space" (henceforth called TPIS)

c. "things external to our minds" (henceforth called TETM)

TMWS can be defined as those things which can be perceived by us by use of one or more of the five senses and that possess extension. It includes things like tables, chairs, etc. but excludes things like the sky or reflections in mirrors of which extension might be a debatable property.

TPIS can be defined as those things which in addition to being perceived by the senses also include those that are "available only to the mind". These, therefore, include things like seeing double images, ghost images, feelings of pleasure and pain, etc.

TETM can be defined so that it includes TMWS + such things that are "available only in the minds of being's other than ourselves" e.g. pain felt by other animals, etc.

Now, Moore says that things like shadows which are part of TMWS may not be in TPIS (since the former includes things that might be perceived but are not necessarily perceived at any time and hence do not belong to the latter). Clearly, TPIS is wider than TMWS by its very definition. Of these, to prove the external world, Moore is concerned with TMWS and TETM.

Moore's wants to show that there are things that they Ð''external to us' or in other words, things that exist independently of anyone having any specific experience of them. He takes various examples such as his body having existed independently even when he was in deep sleep and hence was not "consciously experiencing it". He also gives the example of soap bubbles exhibiting the same behavior such that they don't depend on anyone's experience to exist. Now, his task becomes simple in that all he has to do it point out two (or more) things that can Ð''exist independently of experience' and belong to TMWS. This would mean they automatically belong to TETM. Therefore, it would show that there are things belonging to the external world. He chooses to use the proof of the kind Ð'- Ð''here is my left hand, here is my right hand and now here are two hands. This establishes that they belong to the external world. QED'

Alice Ambrose's position (From: Philosophy of G E Moore, Editor P A Schilpp)

Ambrose fully supports Moore's proof of the external world and her focus is on showing that the skeptic's position