Philosophical Scepticism Analysis

In The Significance of Philosophical Scepticism, Stroud examines the extent to which Moore's evidence succeeds in refuting skepticism, in chapter 3 named ‘G. E. Moore and scepticism: “internal” and “external”’. In his judgment he seeks to grant an intuitive reaction to this abrupt proof; To the feeling that Moore's proposals have the generality necessary to refute the skeptic, but that, in spite of everything, Moore does not answer the question of the skeptic when he raises one hand and then another. Here is the example given by Moore:

(1) ‘Here is a hand.’ then, making the same gesture with the left hand, he says,
(2) ‘Here is another’; he then concludes,
(3) ‘There are at present two human hands.’ Since the conclusion concerns the existence of objects which can be met in space,
Moore claims that (3) entails (4) ‘There are physical objects.’ and hence, that he has proved (5) ‘There is an external world.’

Stroud want to explains this contradiction by differentiating between two ideas of the question concerning our knowledge, and two reactions which are an internal reaction and an external reaction. For the internal reaction, we answer the question "do you know p?" by establishing

To ask such a question, however, does not produce a change of context according to Moore. Nor does it show the context of sensitivity of knowledge, let alone the relativity of knowledge to different standards of evaluation. On the contrary, it depends on an invariant concept and raises another question. Not if we know that p, but rather how one can prove that p is known (if it is true). Moore, moreover, agrees that he cannot answer such a question. Yet, as we have seen many times, he refuses to agree with the skeptic because he cannot answer this question, it follows that we do not know that