SCIENTIFIC FAITH AND WORKS 113 



a ship finds its position by means of observations with the sextant, or 

 when an engineer constructs a dynamo with the aid of a drawing and 

 data known to be correct, he does not engage in scientific thought, 

 although he makes use of experience previously collected. When the 

 computer in the office of the Nautical Almanac computes an eclipse of 

 the moon, foretelling it to a second of time several years before the 

 event, he is not engaged in scientific thought, but is making use of 

 technical skill. When, on the other hand, Adams and Leverrier, com- 

 puting the positions of the planet Uranus, found them not verified in 

 fact, but by the assumption of a new hypothesis, were able to discover 

 the planet Neptune, they were engaged in scientific thought of a high 

 order. The collection of facts, as one collects postage stamps or coins, 

 does not constitute science. In order to have science the facts must be 

 fitted into a definite system, in accordance with a classification on the 

 basis of what we call laws. It is a prerequisite for the existence of any 

 science whatever that we admit that nature is subject to uniformity, 

 that is, that similar circumstances of similar things will be followed 

 by similar results. The belief that the order of nature is reasonable, 

 that is, that there is a correspondence between her ways and our 

 thoughts, and that this correspondence can be found out, is what I 

 have called scientific faith. The method of the inductive sciences, 

 those that concern the facts of nature, is first to observe a class of 

 seemingly related facts in order to find out what they have in common, 

 then if possible to form some hypothesis as to their relation, then to 

 compare the different cases with the hypothesis in order to see whether 

 it is justified. When this process has been successfully carried out, we 

 arc able to predict what will occur in given circumstances, although 

 these circumstances have not occurred. This is what we mean by dis- 

 covering a law of nature, namely, finding a common property of a class 

 of phenomena, such that under all circumstances the phenomena which 

 will ensue can be described. This is what constitutes the difference 

 between scientific and technical thought. Technical knowledge enables 

 us to deal with cases that have occurred before, while scientific knowl- 

 edge enables us to deal with what has not occurred before. 



This is a matter that is not always understood in this country. It 

 is a matter of common knowledge that this country stands very high 

 in technical knowledge, but it is not so often pointed out that her con- 

 tribution to science has as yet been distressingly small. Numerous 

 examples might be given. We have just been celebrating the anniver- 

 sary of Fulton's steamboat, with well-deserved enthusiasm. Neverthe- 

 less we must remember that Fulton did not invent the steamboat, nor 

 did he construct the first one. He combined knowledge then existing 

 with practical sense and business acumen, and was able to build a 



