What I am saying is no more than this: that I should cultivate the scientific spirit. Many eminent men of science do not have this spirit outside their special province; I should seek to make it all-pervasive. The scientific spirit demands in the first place a wish to find out the truth; the more ardent this wish, the better. It involves, in addition, certain intellectual qualities. There must be preliminary uncertainty, and subsequent decision according to the evidence. We must not imagine in advance that we already know what the evidence will prove. Nor must we be content with a lazy scepticism, which regards objective truth as unattainable and all evidence as inconclusive. We should admit that even our best-founded beliefs probably stand in need of _some_ correction; but truth, so far as it is humanly attainable, is a matter of degree. Our beliefs in physics are certainly less false now than they were before the time of Galileo. Our beliefs as to child psychology are certainly nearer to the truth than Dr. Arnold’s were. In each case, the advance has come through substituting observation for preconceptions and passions. It is for the sake of this step that preliminary uncertainty is so important. It is necessary, therefore, to teach this, and also to teach the skill required for marshalling evidence. In a world where rival propagandists are perpetually blazing falsehoods at us, to induce us to poison ourselves with pills or each other with poison gases, this critical habit of mind is enormously important. Ready credulity in the face of repeated assertions is one of the curses of the modern world, and schools should do what they can to guard against it. Throughout the later school years, even more than earlier, there should be a sense of intellectual adventure. Pupils should be given the opportunity of finding out exciting things for themselves after their set tasks were done, and therefore the set tasks should not be too heavy. There must be praise whenever it is deserved, and although mistakes must be pointed out, it should be done without censure. Pupils should never be made to feel ashamed of their stupidity. The great stimulus in education is to feel that achievement is possible. Knowledge which is felt to be boring is of little use, but knowledge which is assimilated eagerly becomes a permanent possession. Let the relation of knowledge to real life be very visible to your pupils, and let them understand how by knowledge the world could be transformed. Let the teacher appear always the ally of the pupil, not his natural enemy. Given a good training in the early years, these precepts will suffice to make the acquisition of knowledge delightful to the great majority of boys and girls. CHAPTER XVII DAY SCHOOLS AND BOARDING SCHOOLS