556 LOGIC OF THE MORAL SCIENCES. 



in ignorance of the careful selection and elaborate comparison of 

 instances required for the formation of a sound theory, attempt to 

 found one upon a few coincidences which they have casually noticed. 



The erroneous method of which we are now to treat is, on the con- 

 trary, peculiar to thinking and studious minds. It never could have 

 suggested itself but to persons of some familiarity with the nature of 

 scientific research ; who — being aware of the impossibility of establish- 

 ing, by casual observation or direct experimentation, a true theory of 

 sequences so complex as are those of the social phenomena — have 

 recourse to the simpler laws which are immediately operative in those 

 phenomena, and which are no other than the laws of the nature of the 

 human beings therein concerned. These thinkers perceive (what the 

 partisans of the chemical or experimental theory do not) that the phi- 

 losophy of society is a deductive science. But, from an insufficient 

 consideration of the specific nature of the subject matter — and often 

 because (their own scientific education having stopped short in too 

 early a stage) geometry stands in their minds as the type of all deductive 

 science ; it is to geometry, rather than to astronomy and natural phi- 

 losophy, that they unconsciously assimilate the deductive science of 

 society. 



Among the differences between geometry (a science of coexistent 

 facts, altogether independent of the laws of the succession of phe- 

 nomena) and those physical Sciences of Causation which have been 

 rendered deductive, the following is one of the most conspicuous : 

 That geometry affords no room for what so constantly occurs in me- 

 chanics and its applications, the case of conflicting forces; of causes 

 which counteract or modify one another. In mechanics we continually 

 find two or more moving forces pi'oducing, not motion, but rest ; or 

 motion in a different direction fi'om that which would have been pro- 

 duced by either of the generating forces. It is true that the effect of 

 the joint forces is the same when they act simultaneously, as if they had 

 acted one after another, or by turns ; and it is in this that the difference 

 between mechanical and chemical laws consists. But still the effects, 

 whether produced by successive or by simultaneous action, do, wholly 

 or in part, cancel one another : what the one force does, the other, 

 partly or altogether, undoes. There is no similar state of things in 

 geometi-y. The result which follows from one geometrical principle 

 has nothing that contradicts the result which follows from another. 

 What is proved true from one geometrical theorem, what would be 

 true if no other geometrical principles existed, cannot be altered and 

 made no longer true by reason of some other principle. What is once 

 proved true must be true in all cases, whatever supposition may be 

 made in regard to any other matter. 



Now a conception, similar to this last, would appear to have been 

 formed of the social science, in the minds of the earlier of those who 

 have attempted to cultivate it by a deductive method. Mechanics 

 would be a science very similar to geometry, if every motion resulted 

 from one force alone, and not from a conflict of forces. In the 

 geometrical theory of society, it seems to be supposed that this is 

 really the case with the social phenomena; and that each of them 

 results always from only one force, one single property of human 

 nature. 



At the point which we have now reached, it cannot be necessary to 



