OBJECTS.] INTRODUCTORY. 93 



other of these two great provinces of nature. The 

 sciences of Astronomy, Mineralogy, Physics, and 

 Chemistry deal with the former, while Biology, with 

 its two divisions of Zoology and Botany, treats of 

 the latter. But natural knowledge is not exhausted 

 by this catalogue of its topics. In the very first para- 

 graph of this Primer, in fact, we had occasion to 

 draw a distinction between Things, or material ob- 

 jects, and Sensations ; and a moment's reflection 

 is sufficient to convince you that sensations are not 

 material objects. A smell takes up no space and has 

 no weight ; and to speak of a pound or of a cubic 

 foot of sound, or of brightness, is, on the face of the 

 matter, an absurdity. Pleasure is said metaphorically 

 to be fugitive, but you cannot imagine a pleasure as 

 a thing in motion. 



What we call our Emotions are in like manner 

 devoid of all the characters of material bodies. Love 

 and hatred, for example, cannot for a moment be con- 

 ceived to have shape, or weight, or momentum. And 

 when, in reasoning, we think, our Thoughts have 

 the same lack of the qualities of material things. 



Sensations, emotions, and thoughts, thus constitute 

 a peculiar group of natural phenomena, which are 

 termed mental. 



67. The order of Mental Phenomena : Psy- 

 chology. 



A definite order obtains among mental phenomena, 

 just as among material phenomena ; and there is no 

 more chance, nor any accident, nor uncaused event, in 

 the one series than there is in the other. Moreover, 

 there is a connection of cause and effect between 



