way of attacking problems is known and where an elaborate technique has been built up, there is plenty of room for valuable routine work. All the difficult preliminary work of getting right conceptions and principles has been done. The routine worker can measure the electric capacities of different condensers because the difficult notion of electric capacity has been made clear by his masters. But the routine worker in psychology who measures “intelligence” is not doing anything definite at all. His subject is not yet ripe for the application of such exact methods. In this way the prestige of physics has exerted a harmful influence on the study of psychology. It is true that some experimental psychologists are becoming aware of the fact that they do not always know what they are measuring. There are controversies as to what a given set of measurements has measured, and some measurements seem to be undertaken on the off-chance that a meaning will some day be found for them. It is not suggested that all experimental psychology is of this kind, but it is certainly true that many psychological papers, complete with correlation coefficients and “curves” of all kinds, wear an air of precision to which they have no real claim. A more definitely materialistic bias is observable in the attempts to explain psychological happenings in terms of physiology. The result is that learned and acute men, caught in the jungle of neurology, painfully fight their way out with some such epoch-making discovery as that one learns a subject more rapidly if one is interested in it. This result, which is supposed to be incompatible with the purely physiological theory of the mind, owes all its difficulty to that in compatibility. Otherwise it is a perfectly obvious fact of experience. If it were not for the prestige achieved by materialism in the Victorian age it is probable that psychology would be very much further advanced than it is. But the side-tracking influence of that philosophy has meant that psychologists have had painfully to discover the obvious. But if materialism, in small doses, delays the recognition of the obvious, it does, when fully developed, deny the obvious. This is what the behaviourists do. They deny that we think or that we can form images in our minds. The only possible answer to this theory is a satire, as when Voltaire answered the theory that in this world everything is for the best in the best of all possible worlds by writing _Candide_. But in this queer modern world behaviourism, instead of being greeted with laughter, is answered carefully and politely, apparently in the spirit in which Monsieur Bergeret shook hands with the _vers libriste_ poet, “for fear of wronging beauty in disguise”. The position of the ordinary man in face of these theories is, nevertheless, a difficult one. Behaviourism may sound to him nonsense, but so does non-Euclidean geometry. His natural reaction would be to class both of them with the theory that the English