Curiously enough, the key to the matter may be found in the fact that the old notion of experience was itself a product of experience--the only kind of experience which was then open to men. If another conception of experience is now possible, it is precisely because the quality of experience as it may now be lived has undergone a profound social and intellectual change from that of earlier times. The account of experience which we find in Plato and Aristotle is an account of what Greek experience actually was. It agrees very closely with what the modern psychologist knows as the method of learning by trial and error as distinct from the method of learning by ideas. Men tried certain acts, they underwent certain sufferings and affections. Each of these in the time of its occurrence is isolated, particular--its counterpart is transient appetite and transient sensation. But memory preserves and accumulates these separate incidents. As they pile up, irregular variations get cancelled, common features are selected, reinforced and combined. Gradually a habit of action is built up, and corresponding to this habit there forms a certain generalized picture of an object or situation. We come to know or note not merely this particular which as a particular cannot strictly be known at all (for not being classed it cannot be characterized and identified) but to recognize it as man, tree, stone, leather--an individual of a certain kind, marked by a certain universal form characteristic of a whole species of thing. Along with the development of this common-sense knowledge, there grows up a certain regularity of conduct. The particular incidents fuse, and a _way_ of acting which is general, as far as it goes, builds up. The skill develops which is shown by the artisan, the shoemaker, the carpenter, the gymnast, the physician, who have regular ways of handling cases. This regularity signifies, of course, that the particular case is not treated as an isolated particular, but as one of a kind, which therefore demands a _kind_ of action. From the multitude of particular illnesses encountered, the physician in learning to class some of them as indigestion learns also to treat the cases of the class in a common or general way. He forms the rule of recommending a certain diet, and prescribing a certain remedy. All this forms what we call experience. It results, as the illustration shows, in a certain general insight and a certain organized ability in action.