189 
live exercise of power according to the law of design. That plea- 
sure is felt, and the condition is good, when the operations of the 
forces by which the organism is built up as a whole are in accord- 
ance with the ends arrived at, and with the order fixed for those 
ends ; that, on the contrary, pain is felt, and the condition is evil 
when disorder arises, and the results are in disaccordance with the 
ends aimed at. It is necessary to bear in mind that the ideas in- 
cluded in general terms correlate each other in psychology as well 
as in physics. Thus Order, regard being had to its results, is logi- 
cally correlative with Good ; for good in creation is the result of order, 
and of order alone. Order, again, is as general a law as design ; 
consequently the deviations from the primary law of design, known 
as evils, are correlative with, and derivative from the primary law of 
order, just as the physical and vital forces are derivative from the 
primary forces. Again, perfection correlates the law of order and 
the law of unity; for, admitting that there are degrees of perfec- 
tion, the highest perfection is attained when, with the greatest mul- 
tiplicity or differentiation of parts, there is the most complete unity, 
or adaptation of those parts to each other as ends and means. This 
is the perfection of society as well as of organisms. 
In biology , the author shows that the laws of unity of type and 
permanence of species are compatible with an empirical law of life — 
the law of incessant change. The adaptation of an organism to the 
external world is instinct ; but since the operations of the forces of 
the external world which maintain life, as heat, light, and the like, 
are constantly varying, so, according to the teleological law, must 
the phenomena of life and instinct be constantly varying. Hence, 
correlative with the fixed and immutable law of design, as mani- 
fested in unity of type, and derivative therefrom, is the law of in- 
cessant change; and this is a primary law of creation as well as of 
life. For, just as the motion of a planetary body round a centre or 
centres is due to incessant variations (as marked by every point in 
the described curve), caused in the line of direction by a deflecting 
force, so all the variations in organisms, whether animal or vege- 
table, from the first, or correlative law of design, as manifested in 
unity of type, are results of deflecting forces, i. e., of external condi- 
tions, influencing organisms to change from the type in time and space. 
In this way, unity of type and permanence of species are correlative 
with incessant variations in the transmissions of the characters and 
2 B 
VOL. iv. 
