SECTION 15. DEDUCTION. 121 



On circumspectly examining the scope of deductive procedure, 

 it becomes patent that an investigation conducted according to 

 strict scientific rules involves the application of deduction almost 

 as frequently as that of generalisation. Just as from time to 

 time the investigator pushes his enquiry forward, so he loses 

 no occasion for testing the next step which he proposes to make 

 by sounding its implications. That is, instead of securing all 

 his middle axioms by induction, he arrives at many of them 

 through deduction. Naturally, therefore, when he has reached 

 his final generalisation, and has embodied it in a concise state- 

 ment, he will not neglect the momentous duty of probing it 

 deductively. Thus deduction is no stranger to generalisation, 

 and by further compelling exactness in statement at every 

 turn, it is of double benefit to him who generalises. 



A deduction to be scientifically permissible and serviceable 

 must be grounded on a proposition well rooted in verified data, 

 for without this we are back in the age of scholasticism and 

 obscurantism. In fact, in modern enquiries a large number of 

 verified propositions are commonly employed to enable a single 

 deduction to be made. Theoretically speaking, it might be as 

 convenient to discover classes of facts by going backwards as by 

 proceeding forwards. In practice, however, the reverse is empha- 

 tically the case, and this constitutes the justification for seeking 

 for the fullest, as for the most comprehensive, generalisations. 

 For example, by attentively watching an individual who is 

 quick in his ways, we might finally discern the rationale of 

 quickness "a settled and eager desire to be expeditious, 

 coupled with fair intelligence, study of others who are ex- 

 peditious, and adequate practice", from which the diverse 

 methods he employs should follow logically. Yet, in reality, 

 the mere knowledge of the statement which subsumes the 

 inductive enquiry would deductively yield with great difficulty 

 a paucity of information, and much of this would be spurious. 

 Granted, however, the inductive statement, and a certain 

 number of the details on which it is based to illustrate its 

 inwardness, and methodised deductive procedure (see Con- 

 clusion 31) will yield substantial additions. For the sake, 

 therefore, of deduction, we plead that generalisations shall be 

 as full as possible, in order that the task imposed on it shall 

 not be excessive. 



If a deduction needs to be rooted in justifiable generalisations 

 or facts, it must be no less subject to rigid verification, for a 

 merely plausible deduction has no more value than a merely 

 specious generalisation. Deduction, again, is fertile, in proportion 



of Idioplasma-Teilchen. Then Weisner, also a botanist, who spoke of the 

 Plassomes. Our own Prof. Whitman attributed to his life units certain other 

 essential qualities and called them idiosomes. A German zoologist, Haake, 

 has called them gemmules. Another German writer, a Leipsic anatomist 

 Altmann, calls them granuli." (C. S. Minot, op.cit., pp. 234-235.) 



