General Mental Progress due to research. 85 



that mental action is largely consistent with the great 

 principles of science ; not that in our present state 

 of knowledge, mental phenomena can be entirely ex- 

 plained by them, or that mental actions involve 

 nothing more than physical and chemical processes. 



That mental progress is advanced by scientific dis- 

 covery is a common circumstance. Our ideas of facts, 

 our knowledge of general principles, our views of man, 

 of nature, and of the Universe ; and even our modes 

 of thought, have been gradually and profoundly 

 changed by the new knowledge acquired by means of 

 scientific research. This truth is capable of being 

 most extensively illustrated by a multitude of facts in 

 the whole of the sciences, and in the arts, manufac- 

 tures, and other subjects dependent upon science. 

 For example, in astronomy, great changes, produced 

 by the results of scientific discovery have taken place 

 in our ideas respecting the magnitude of Space and of 

 the Heavenly bodies, the constitution, form, and 

 motion of the Earth, the functions of the Sun and 

 Moon, the distances of the Sun and fixed Stars, the 

 nature of eclipses and comets ; and a great many 

 other matters. In terrestrial physics, the mental 

 advances have been equally great in our ideas respect- 

 ing the causes of tides and of winds, the pressure of 

 the atmosphere, the existence and course of the Gulf 

 Stream, the physical conditions of the Equator and 

 Poles, the conditions upon which day and night, 

 summer and winter depend, the depth of the ocean, 

 the height of the atmosphere, the cause of rainbows, of 



