Thus we may take it as an observed fact that, so far as overt behaviour is concerned, there are two objections to the type of theory with which we began, when considered as covering the whole field. The first objection is that in cases of a certain kind, the solution appears sooner than it should according to the doctrine of chances; the second is that it appears as a whole, i.e. that the animal, after a period of quiescence, suddenly goes through the right series of actions smoothly, and without hesitation.
Where human beings are concerned, it is difficult to obtain such good data as in the case of animals. Human mothers will not allow their children to be starved, and then shut up in a room containing a banana which can only be reached by putting a chair on the table and a footstool on the chair, and then climbing up without breaking any bones. Nor will they permit them to be put into the middle of a Hampton Court maze, with their dinner getting cold outside. Perhaps in time the State will perform these experiments with the children of political prisoners, but as yet, perhaps fortunately, the authorities are not sufficiently interested in science. One can observe, however, that human learning seems to be of both sorts, namely, that described by Watson and that described by Köhler. I am persuaded that speech is learnt by the Watsonian method, so long as it is confined to single words: often the trial and error, in later stages, proceeds sotto voce, but it takes place overtly at first, and in some children until their speech is quite correct. The speaking of sentences, however, is already more difficult to explain without bringing in the apprehension of wholes which is the thing upon which Gestaltpsychologie lays stress. In the later stages of learning, the sort of sudden illumination which came to Köhler's chimpanzees is a phenomenon with which every serious student must be familiar. One day, after a period of groping bewilderment, the schoolboy knows what algebra is all about. In writing a book, my own experience—which I know is fairly common, though by no means universal—is that for a time I fumble and hesitate, and then suddenly I see the book as a whole, and have
