The critic and the Sales Manager are not ordinarily regarded as of the same craft, nor are the poet and the advertising agent. It is true that some serious artists are occasionally tempted into poster designing. It is, however, doubtful whether their work pays. But the written appeals which have the soundest financial prospects as estimated by the most able American advertisers are such that no critic can safely ignore them. For they do undoubtedly represent the literary ideals present and future of the people to whom they are addressed.[67] They are tested in a way which few other forms of literature are tested, their effects are watched by adepts whose livelihood depends upon the accuracy of their judgment, and they are among the best indices available of what is happening to taste. Criticism will justify itself as an applied, science when it is able to indicate how an advertisement may be profitable without necessarily being crass. We shall see later under what conditions popularity and possible high value are compatible. The strongest objection to, let us say, the sonnet we have quoted, is that a person who enjoys it, through the very organisation of his responses which enables him to enjoy it, is debarred from appreciating many things which, if he could appreciate them, he would prefer. We must not, of course, forget those variations in psychological efficiency discussed in Chapter XXII as degrees of vigilance. Even a good critic at a sufficiently low ebb of neural potency might mistake such a sonnet for one of Shakespeare’s or with more ease for one of Rossetti’s. But when vigilance was restored he would see, or at least feel, the differences. The point is that a reader who, at a high degree of vigilance, thoroughly enters into and enjoys this class of verse, is necessarily so organised that he will fail to respond to poetry. Time and much varied experience might change him sufficiently, but by then he would no longer be able to enjoy such verse, he would no longer be the same person. A general statement such as this about the incompatibility of inexpressibly complex adjustments must naturally be incapable of strict proof. Individuals with alternating personalities and subject to fugues would have to be considered. So would the phenomena of ‘mutations of regime’ unaccompanied by change of vigilance if such occur. None the less very much evidence substantiates the statement. The experience of all those who have passed through the stages in the development of attitudes presupposed by great poetry is probably conclusive.