ch. in.] THE TEST OF TRUTH. 47 



and objective factors, can never be regarded as a knowledge 

 of the objective factor by itself. This is, indeed, the import 

 of our illustration, above given, from the phenomena of vibra- 

 tory motion. Since a homogeneous phenomenon, like the 

 undulation of molecules, can produce in us such hetero- 

 geneous states of consciousness as the feelings of sound, heat, 

 or colour, we argued that the constitution of the percipient 

 mind must modify in every case the character of the phe- 

 nomenon perceived ; and that, therefore, the phenomenon 

 cannot be regarded as like the external noumenon, its part- 

 cause. What is this but saying, with Leibnitz, that the 

 subject actively cooperates with the object in each act of 

 conscious knowledge ? The Leibnitzian criticism, therefore, 

 only serves to bring out in a stronger light the doctrine 

 that all knowledge is of the Eelative. Though powerful 

 against the hypothesis of Locke, it is powerless against the 

 position held by modern psychology. 



Such a result, however, was the farthest possible from 

 Leibnitz's thoughts. Far from intending to re-enforce the 

 doctrine of relativity as shadowed forth in the writings of 

 the Lockian school, his object was to crush it at the start 

 by showing that we can obtain a criterion of absolute or 

 objective knowledge. And he accordingly gave to his state- 

 ment an interpretation quite inconsistent with the doc- 

 trine of the relativity of knowledge as we are now obliged 

 to hold it. He held that in many acts of cognition, the 

 mind contributes an element of certainty which could 

 never have been gained from experience, which could 

 never have flowed from the intercourse of the mind with 

 its environment ; and that propositions obtained by such 

 acts of cognition are Necessary Truths, — truths which are 

 *;rue of the objective order of things as well of the sub- 

 jective order. 



After Hume, by drawing out the Lockian doctrine to its 

 extreme corollaries, had enunciated a set . •? conclusions which 



