60 Introduction 



time, the teacher might be a student of technology, primarily interested 

 in the technical wonders of our age; his successor might be a classical 

 scholar more at home in the Greek writings; the third might be a medi- 

 aevalist, etc. 



The Hellenist and the mediaevalist would not be as much out of step 

 as one might think, because every teacher would have to satisfy one 

 indispensable requirement. He should be deeply familiar with at least 

 one branch of today's science and he should have a more superficial 

 acquaintance with various other branches. By deep familiarity is meant 

 work at the front, experimental work in the laboratory or observational 

 work in the observatory or in the field. If he met that requirement, his 

 other learning, whether classical, mediaeval or oriental would not tend to 

 sidetrack him completely. He would remain, first of all, not a historian 

 or a philologist but a historian of science. His scientific training and 

 experience would guarantee his adequate treatment of scientific subjects 

 and would give him the needed authority to talk about them in the 

 presence of young scientists. Nothing can be worse in the teaching of 

 the history of science than learned discussion of topics of which the 

 instructor has no inward knowledge; the more learned, the worse it is. 



Just how detailed should the discussion of a scientific topic be? It 

 is not possible to give a general answer to this question. Each topic 

 will require separate treatment. This much can be said, the students 

 must be given a feeling of concreteness and genuineness which implies 

 a certain amount of detail. Why is precise knowledge always desirable? 

 Simply because we can never be sure of anything unless we know it 

 as exactly as possible. The procedure of our criminal courts is very 

 instructive in that respect. A man cannot be convicted of a murder un- 

 less the circumstances of that murder have been minutely described. 

 The same procedure must be followed in the discovery of truth. A 

 general statement may be right or wrong: the necessary checking is 

 possible only if we come to well defined facts. The history of science 

 is a good means of illustrating that point of view not only for its own 

 sake but also for the strengthening of knowledge and for the unification 

 of mankind. Whatever be the utility of mystical ideas in religion, man- 

 kind cannot be unified on a mystical basis but only on tangible facts, 

 objective, impartial, and controllable knowledge. Darkness covers too 

 many crimes and opens too many opportunities to trouble-makers; truth- 

 fulness and light are the first conditions of social health. 



The teaching of the history of science should be as concrete and 

 clear as possible rather than philosophical and foggy. Its concreteness 

 will be easier to attain if the instructor is given facilities to make a few 

 simple experiments and to illustrate his course with maps, charts and 

 other exhibits. E.g., he should be able to show the students some of 

 the old instruments and demonstrate their use."^^ Such equipment 



'^ It is difficult to explain simple problems, let us say, of mathematical geography 

 or astronomy without models. I have always been embarrassed by the lack of 

 models when I discussed the ancient theories of homocentric spheres, of eccentrics 

 and epicycles. The necessary models should be easily available to the instructor. 



