have understood it only when I have understood it as analytic. To understand means nothing else, that is, than to be clear about the rules governing the use of the words in question; but it is precisely these rules of usage that make statements analytic. If I do not know whether a complex of words constitutes an analytic statement or not, this simply means that at that moment I lack the rules of usage: that therefore I have simply not understood the statement. Thus the case is that either I have understood nothing at all, and then nothing more is to be said, or I know whether the statement which I understand is synthetic or analytic (which of course does not presuppose that these words hover before me, that I am even acquainted with them), In the case of an analytic statement I know at one and the same time that it is valid, that formal truth belongs to it. 

The above doubt concerning the validity of analytic statements was therefore out of order. I may indeed doubt whether I have correctly grasped the meaning of some complex of signs, in fact whether I shall ever understand the meaning of any sequence of words. But I cannot raise the question whether I can ascertain the correctness of an analytic statement. For to understand its meaning and to note its a priori validity are in an analytic statement one and the same process. In contrast, a synthetic assertion is characterized by the fact that I do not in the least know whether it is true or false if I have only ascertained its meaning. Its truth is determined only by comparison with experience. The process of grasping the meaning is here quite distinct from the process of verification.
 
There is but one exception to this. And we thus return to our "confirmations." These, that is, are always of the form "Here now so and so," for example "Here two black points coincide," or "Here yellow borders on blue," or also "Here now pain," etc. What is common to all these assertions is that demonstrative terms occur in them which have the sense of a present gesture, i.e. their rules of usage provide that in making the statements in which they occur some experience is had, the attention is directed upon something observed. What is referred to by such words as "here," "now," "this here," cannot be communicated by means of general definitions in words, but only by means of them together with pointings or gestures. "This here" has meaning only in connection with a gesture. In order