280 GENERAL PRINCIPLES. 



times determined exceptionally rapid changes in the direction or the 

 rate of movement. So also is it in geological history. The eras, 

 periods, etc., usually shade more or less insensibly into each other ; yet 

 there have been times of comparatively rapid or revolutionary change. 

 In all history there are periods of comparative quiet, during which 

 forces of change are gathering strength, separated by periods of more 

 rapid change, during which the accumulated forces produce conspicu- 

 ous effects. 



3. Ages, periods, etc., in all history, whether individual, political, or 

 geological, are determined by the rise, culmination, and decline of suc- 

 cessively higher dominant forces, principles, ideas, functions. Thus, 

 in individual development, we have the culmination, first, of the nutri- 

 tive functions ; then of the reproductive and muscular functions ; and, 

 last, of the cerebral functions. And in mental development, also, we 

 have the culmination, first, of the perceptive faculties, and memory ; 

 then, the imaginative and aesthetic faculties ; and, last, the reflective 

 faculties ; the first gathering and storing material, the second vivifying 

 it, the third using it in productive mason- work of science. In social 

 history, too, the successive culminations of diiferent phases of civiliza- 

 tion have been the result of the introduction and culmination of suc- 

 cessive dominant principles or ideas — of successive social forces or 

 functions. So has it been in geological history. The great divisions 

 of time, especially what are called ages, are characterized by the intro- 

 duction and culmination of successive dominant classes of organisms, 

 for these are the highest expression of earth-life. Thus, in geology, 

 we have an age of mollusks, an age of fishes, an age of reptiles, in 

 which these were successively the dominant class. 



But since (Law 2) successive ages graduate more or less into and 

 overlap each other, we might expect, and do indeed find, that the 

 characteristics of each age commence in the preceding age. Each 

 age is foreshadowed in the previous age. The same is true of all 

 history. 



4. In all history, at the close of an age, the characteristic dominant 

 principle or class declines, but does not perish. It only becomes sub- 

 ordinate to the succeeding dominant class or principle. Thus, to illus- 

 trate from individual history : in youth, the characteristic faculties of 

 childhood, viz., perception and memory, decline, and become subordi- 

 nate to the higher faculty of imagination, and this in turn becomes sub- 

 ordinate to the still higher faculty of productive thought ; and thus the 

 whole organism becomes higher and more complex, each stage of devel- 

 opment including not only its own characteristic, but also, in a subordi- 

 nate degree, those of all preceding stages. The same is true of social 

 history. Each stage of social development absorbs and includes the 

 social principles and forces characteristic of previous stages, but subor- 



