=Adjusting instruction to the capacities of your students=
Third, do not be afraid to utilize commonplace facts and illustrations. A successful professor of sociology writes me that he can remember that what are mere commonplaces now were revelations to him at twenty-one. Two of the greatest teachers of the nineteenth century, Faraday and Huxley, attributed their success to the simple maxim, take nothing for granted. It is safe to assume that most students come from homes where business and petty neighborhood doings are the chief concern, and where a broad, well-informed outlook on life is rare. Since so many of my colleagues insist that young Ph.D.'s tend constantly to "shoot over the heads" of their students, the best way of avoiding this particular pitfall seems to lie along the road of simple, elementary, concrete fact. The discussion method in the classroom will soon put the instructor right if he has gone to the other extreme of depreciating his students through kindergarten methods. Likewise he can guard against being oracular and pedantic by letting out his superior stores of information through free discussion in the Socratic fashion. Nothing is more important to good teaching than the knack of apt illustration. While to a certain extent it can be taught, just as the art of telling a humorous story or making a presentation speech can be communicated by teachers of oral English, yet in the long run it is rather a matter of spontaneous upwellings from a well-stored mind. For example, suppose a class is studying the factors of variation and selection in social evolution: the instructor shows how Nature loves averages, not only by statistics and experiments with the standard curve of distribution, but also, if he is a really illuminated teacher, by reference, say, to the legend of David and Goliath, the fairy tale of _Little One-Eye, Little Two-Eye, Little Three-Eye_, and Lincoln's famous aphorism to the effect that the Lord must love the common people because he made so many of them. Sad experience advises that it is unsafe for an instructor any longer to assume that college sophomores are familiar with the Old Testament, classic myths, or Greek and Roman history. Hence he must beware of using any recondite allusions or illustrations which themselves need so much explanation that their bearing on the immediate problem in hand is obscured. An illustration, like a funny story, loses its pungency if it requires a scholium.