"To yourself, Professor, the practical aspect seems comparatively insignificant?" "I did not say that, and it was not implied in the question. We must not lose sight of our premises. As long as I am interested in working along lines of research--this was the assumption--the practical aspect, that is, every practical result that is found simultaneously or arises out of it later, is a matter of complete indifference to me." Far be it from me, even in thought, to wish to question this confession of faith, particularly as the fact that it comes from a searcher of the truth gives it the more weight. Yet a certain uneasiness has crept over me because voices have recently made themselves heard that demand for science a totally different tendency. They arise not only from the public at large, but also from academic circles. Just a short time ago I read an exposition by a well-known scientist, W. Wien, in which he indulged in a violent polemic against the view that purely scientific objects are alone valid. Professor Wien addressed himself particularly to German physicists, reproaching them with underestimating technical science, and with regarding it as a "lowering of status" when a physicist enters into practical life. To this Einstein remarked: "I do not know at whom this reproach is aimed, but I venture to think that my own attitude can never have given rise to an attack of this kind. For I make no divisions of rank, and recognize no higher and no lower status. I affirm only what is the nature of science herself, and the objects according to which she, objectively, has to direct her gaze. Whatever further orientation individual investigators may seek for themselves depends on the determining conditions of life of each, although these conditions do not serve as a means for deducing the main lines of research. The accusation that I am unwarranted in putting forward this view will, I hope, not be levelled at me, for my connexions with practice are manifold enough, and up to the present moment I have often collaborated with practical physicists...." "As I have regretfully observed when you were obliged to interrupt a conversation with me to give an audience to impatient persons seeking advice in technical matters!"