and that therefore the truth or falsity of the assertion could never be tested, the reply would be that if the words 'supercelestial space' are to have any meaning at all, that space must be defined in such a way that the impossibility of reaching it or of perceiving anything in it would be merely empirical, so that some means of overcoming the difficulties could at least be described, although it might be beyond human power to put them into use.
Thus our conclusion stands. The hypothesis of immortality is an empirical statement which owes its meaning to its verifi ability, and it has no meaning beyond the possibility of verification. If it must be admitted that science could make no experiment the negative result of which would disprove it, this is true only in the same sense in which it is true for many •other hypotheses of similar structure — especially those that have sprung up from other motives than the knowledge of a great many facts of experience which must be regarded as giving a high probability to the hypothesis. The question about the 'existence of the external world' will be discussed in the next section.
V
Let us now turn to a point of fundamental importance and the deepest philosophic interest. Professor Lewis refers to it as the "egocentric predicament", and he describes as one of the most characteristic features of logical positivism its attempt to take this predicament seriously. It seems to be formulated in the sentence (128), "Actually given experience is given in the first person", and its importance for the doctrine of logical positivism seems to be evident from the fact that Carnap, in his Der logische Aufbau der Welt, states that the method of this book may be called "methodological solipsism". Professor Lewis thinks, rightly, that the egocentric or solipsistic principle is not implied by our general principle of verifiability, and so he regards it as a second principle which, together with that of verifiability, leads, in his opinion, to the main results of the Viennese philosophy.
If I may be permitted to make a few general remarks here I should like to say that one of the greatest advantages and attractions of true positivism seems to me to be the antisolipsistic attitude which characterizes
