TERMINOLOGY AND NOMENCLATURE. 263 



validity of a reasoning can be apparent to any person who has 

 looked only at the form of the process. Whoever has assented 

 to what was said in the last Book concerning the case of 

 the Composition of Causes, and the still stronger case of the 

 entire supersession of one set of laws by another, is aware 

 that geometry and algebra are the only sciences of which the 

 propositions are categorically true : the general propositions of 

 all other sciences are true only hypothetically, supposing that 

 no counteracting cause happens to interfere. A conclusion, 

 therefore, however correctly deduced, in point of form, from 

 admitted laws of nature, will have no other than an hypo- 

 thetical certainty. At every step we must assure ourselves 

 that no other law of nature has superseded, or intermingled 

 its operation with, those which are the premises of the 

 reasoning; and how can this be done by merely looking at 

 the words? We must not only be constantly thinking of 

 the phenomena themselves, but we must be constantly study- 

 ing them ; making ourselves acquainted with the peculiarities 

 of every case to which we attempt to apply our general 

 principles. 



The algebraic notation, considered as a philosophical lan- 

 guage, is perfect in its adaptation to the subjects for which 

 it is commonly employed, namely those of which the investi- 

 gations have already been reduced to the ascertainment of a 

 relation between numbers. But, admirable as it is for its 

 own purpose, the properties by which it is rendered such are 

 so far from constituting it the ideal model of philosophical 

 language in general, that the more nearly the language of any 

 other branch of science approaches to it, the less fit that lan- 

 guage is for its own proper functions. On all other subjects, 

 instead of contrivances to prevent our attention from being 

 distracted by thinking of the meaning of our signs, we ought 

 to wish for contrivances to make it impossible that we should 

 ever lose sight of that meaning even for an instant. 



With this view, as much meaning as possible should be 

 thrown into the formation of the word itself; the aids of 

 derivation and analogy being made available to keep alive a 



