CHAP. III.] DERIVATION OF THE LAWS. 39 



CHAPTER III. 



DERIVATION OF THE LAWS OF THE SYMBOLS OF LOGIC FROM THE 

 LAWS OF THE OPERATIONS OF THE HUMAN MIND. 



1. HPHE object of science, properly so called, is the knowledge 

 -- of laws and relations. To be able to distinguish what 

 is essential to this end, from what is only accidentally associated 

 with it, is one of the most important conditions of scientific pro- 

 gress. I say, to distinguish between these elements, because a con- 

 sistent devotion to science does not require that the attention 

 should be altogether withdrawn from other speculations, often of a 

 metaphysical nature, with which it is not unfrequently connected. 

 Such questions, for instance, as the existence of a sustaining 

 ground of phenomena, the reality of cause, the propriety of forms 

 of speech implying that the successive states of things are con- 

 nected by operations, and others of a like nature, may possess 

 a deep interest and significance in relation to science, without 

 being essentially scientific. It is indeed scarcely possible to 

 express the conclusions of natural science without borrowing 

 the language of these conceptions. Nor is there necessarily 

 any practical inconvenience arising from this source. They who 

 believe, and they who refuse to believe, that there is more in the 

 relation of cause and effect than an invariable order of succession, 

 agree in their interpretation of the conclusions of physical astro- 

 nomy. But they only agree because they recognise a common ele- 

 ment of scientific truth, which is independent of their particular 

 views of the nature of causation. 



2. If this distinction is important in physical science, much 

 more does it deserve attention in connexion with the science of 

 the intellectual powers. For the questions which this science 

 presents become, in expression at least, almost necessarily mixed 

 up with modes of thought and language, which betray a meta- 

 physical origin. The idealist would give to the laws of reasoning 



