28 



SCIENCE 



[N. 8. Vol. XLV. No. 1150 



must depend first on a knowledge of its 

 component parts and their functions. This 

 analysis or dissection not only must pre- 

 cede, but seems at once more intimatelj 

 scientific than the synthetic stage that fol- 

 lows. I here use the word "scientific" in 

 the specialized sense of acquiring data con- 

 cerning natural phenomena. The second 

 or synthetic stage is more metaphysical in 

 that it considers data that have been ac- 

 quired in their relation to one another. 

 The first phase is more intimately scientific, 

 then, in that we are actually in contact with 

 those elements which we describe as facts. 

 The second or synthetic stage is, however, 

 fully as essential to progress in that with- 

 out it we should never pass from a known 

 group of facts to one that is unknown. 

 The synthesis oi; small or less certain 

 groups of facts gives rise to the working 

 hypothesis which, in its proving or disprov- 

 ing, leads to other facts. Larger or more 

 certain groupings of fact constitute a 

 theory which, in its restatement of evi- 

 dence, serves as a point of departure for 

 further advance. A theory may stand for 

 an indefiLnite period as a complete state- 

 ment of the facts with which it deals, or it 

 may soon be supplanted by a better one. 

 In either case it has its heuristic value. 



In eliciting facts certain methods are re- 

 quired, in the larger sense methods of dis- 

 covery, in a more restricted sense methods 

 of technical precision. It might be thought 

 that in methods of discovery, certainly, a 

 knowledge of the methods of other sciences 

 would be essential, and so indeed they are, 

 but in no exclusive sense. It has never 

 ceased to surprise me to find from conver- 

 sations with my colleagues in other branches 

 that all experienced investigators employ 

 the same methods of discovery — the mate- 

 rials we handle may be as diverse as you 

 like, the technical details incomprehensible 



to one another, and yet the methods of at- 

 tack on the unknown remain the same. We 

 all gravitate through experience into the 

 same channels of reasoning, the same meth- 

 ods of planning experiments, of erecting 

 working hypotheses, of rejecting them when 

 they fail of verification, or of trying them 

 further when they pass the first test satis- 

 factorily. 



There remain, then, methods of tech- 

 nical precision. For the purpose of this 

 discussion of the usefulness to the biolog- 

 ical medical sciences of more fundamental 

 or of merely contributory sciences, we may 

 consider methods of technical precision as 

 statistical, instrumental or expeiimental. 

 No claim is made as to the inclusiveness of 

 this cataloguing. 



There is some dispute, I believe, as to 

 whether statistics constitute a separate sci- 

 ence or merely a method. At all events, sta- 

 tistics are used as a method in all sciences 

 or groupings of fact. Of late, statistics are 

 used to a large extent in certain biological 

 work, notably in the branch of hygiene deal- 

 ing with vital statistics, and in certain more 

 theoretical branches as the laws of heredity 

 (Mendelism). It is obvious that any sci- 

 ence which in its analytic phase accumu- 

 lates a mass of figures or data will need 

 statistical methods. I am not aware that 

 statistical methods can be learned apart 

 from the constituent facts which they are 

 aimed to elucidate. It seems to me that 

 such methods are best learned by using 

 them, and that there is no particular object 

 in learning the use of statistical methods in 

 reference to wages, let us say, for the pur- 

 pose of applying them in investigations of 

 the incidence of tuberculosis. In either 

 case we must refer to treatises written by 

 those who have used statistics extensively 

 both for the general methods and causes of 

 error involved in their use. Statistics, to 

 repeat, is not a separate science, but a 



