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included under sociology, is impossible. But physiology is itself a 
derivative science, inasmuch as vital processes are primarily depen- 
dent upon certain molecular forces of matter, known as light, heat, 
chemical affinity, &c. Consequently, if philosophy cannot be separated 
from physiology or the science of vital function, neither can physio- 
logy be separated from physics. Philosophy, therefore, ought to 
include in one harmonious and comprehensive body of doctrine all 
the fundamental principles of the natural sciences. It would to 
this end take cognisance of three great departments of human know- 
ledge — the physical, the vital or biological, and the metaphysical. 
The author next shows that as science has already developed in 
each of these departments a number of general laws which only 
await higher generalizations to bring them all under laws still more 
general, and thus secure that unity of the sciences to which they all 
tend, it is the proper business of philosophy to supply those higher 
generalizations. These, the author argues, must be derived from 
the common sense and experience of mankind ; for that experience 
consists in a knowledge of the laws of nature, — not formularized, it 
is allowed, in express propositions, — but acted upon by man in all 
his relations. The experience of mankind is expressed, however, in 
at least three different, yet closely related modes — namely, in his lan- 
guage, in the laws which regulate his conduct as a social being, and 
in his conduct as an individual. If man’s experience of the great 
uniformities of nature, as expressed in these three modes, can be 
compared with the results of scientific research and formularized 
into general propositions, these propositions will express fundamental 
empirical laws fit to be received amongst the highest generalizations 
of philosophy, considered as a practical knowledge of the general laws 
of nature. After having shown by illustrations the application of 
this method of deducing general empirical laws, the author pro- 
ceeds to examine the generalizations or fundamental ideas implied 
in the words law , force } mind. 
The term law, as commonly used, denotes the written or spoken 
words in or by which is expressed the will of any person or persons, 
having the power to compel others to adapt their conduct to the will 
so expressed. Conduct so compelled would be a uniform succession 
of events occurring according to law. In science, whenever a uni- 
form succession of events or of phenomena in nature is observed to 
take place, the expression in words or signs of that uniformity is 
