CHAPTER XIX. 



THE INSTABILITY OF THE HOMOGENEOUS.* 



149. THE difficulty of dealing with transformations so 

 many-sided as those which all existences have undergone, 

 or are undergoing, is such as to make a definite or complete 

 deductive interpretation seem almost hopeless. So to grasp 

 the total process of re-distribution of matter and motion, as 

 to see simultaneously its several necessary results in their 

 actual inter-dependence, is scarcely possible. There is, how- 

 ever, a mode of rendering the process as a whole tolerably 

 comprehensible. Though the genesis of the re-arrangement 

 undergone by every evolving aggregate, is in itself one, it 

 presents to our intelligence several factors; and after in- 

 terpreting the effects of each separately, we may, by syn- 

 thesis of the interpretations, form an adequate conception. 



On setting out, the proposition which comes first in logi- 

 cal order, is, that some re-arrangement must result; and this 

 proposition may be best dealt with under the more specific 

 shape, that the condition of homogeneity is a condition of 

 unstable equilibrium. 



First, as to the meaning of the terms; respecting which 

 some readers may need explanation. The phrase unstable 

 equilibrium is one used in mechanics to express a balance of 

 forces of such kind, that the interference of any further 

 force, however minute, will destroy the arrangement previ- 



* The idea developed in this chapter originally formed part of an article 

 on "Transcendental Physiology," published in 1867. See Essays, pp. 



279-290. 



412 



