you cannot give meaning to a sentence by discovering a method of verifying it, but only by stipulating how it shall be done. Thus logical possibility or impossibility of verification is always selfimposed. If we utter a sentence without meaning it is always our own fault.
The tremendous philosophic importance of this last remark will be realized when we consider that what we said about the meaning of assertions applies also to the meaning of questions. There are, of course, many questions which can never be answered by human beings. But the impossibility of finding the answer may be of two different kinds. If it is merely empirical in the sense defined, if it is due to the chance circumstances to which our human existence is confined, there may be reason to lament our fate and the weakness of our physical and mental powers, but the problem could never be said to be absolutely insoluble, and there would always be some hope, at least for future generations. For the empirical circumstances may alter, human facilities may develop, and even the laws of nature may change (perhaps even suddenly and in such a way that the universe would be thrown open to much more extended investigation). A problem of this kind might be called practically unanswerable or technically unanswerable, and might cause the scientist great trouble, but the philosopher, who is concerned with general principles only, would not feel terribly excited about it.
But what about those questions for which it is logically impossible to find an answer? Such problems would remain insoluble under all imaginable circumstances; they would confront us with a definite hopeless Ignorabimus; and it is of the greatest importance for the philosopher to know whether there are any such issues. Now it is easy to see from what has been said before that this calamity could happen only if the question itself had no meaning. It would not be a genuine question at all, but a mere row of words with a question-mark at the end. We must say that a question is meaningful, if we can understand it, i.e., if we are able to decide for any given proposition whether, if true, it would be an answer to our question. And if this is so, the actual decision could only be prevented by empirical circumstances, which means that it would not be logically impossible. Hence no meaningful problem can be insoluble in principle.
If in any case we find an answer to be logically impossible we know that we really have not been asking anything, that what sounded like a question
