with human responsibility for taking the right attitude toward
the entire visible and unseen universe. Finally, science and philosophy
are briefly treated as evolved products which include within their scope
all that there is in human knowledge; for this reason they take the
highest place, instead of the position below religion usually assigned to
them. At the last, having reached our final standing ground, we must look
back in order that we may clearly define the lessons and ultimate values
of the whole doctrine of evolution.

* * * * *

Ethics is the science of duty. It is usually restricted to an examination
of purely human obligations, and to a search for the reasons why men
should do certain things and refrain from committing other acts. Like
psychology and sociology, ethics began as a strictly formal and _a priori_
system of dogmas which related to the life of cultured human beings alone.
Again, like the sciences specified, it gradually broadened its scope so as
to include the conventions of races lower in the scale than the civilized
peoples who only were sufficiently advanced intellectually to conceive it.
Thus the comparative method came to be employed, and in direct proportion
to its use, more liberal views have developed regarding the diverse
methods of thought and standards of social life and of conduct among
differently conditioned peoples. Still more important is the demonstration
that human ethics as a whole, like human faculty and civilization, takes
its place at the end of a scale whose beginnings can be found in lower
organic nature.

Those who have followed the account of social evolution given in the
preceding chapter must realize that the basic general principles of
natural ethics, as contrasted with "formal" ethics, have already been
discovered and formulated. A biological association of whatever grade and
degree of complexity is impossible unless biological duties are
discharged. Human ethical conduct differs from insect and protozooen
ethical conduct only in the element of a participation in the process by
the explicit consciousness of man that he has definite obligations to
others; and this distinguishing characteristic is the direct outcome of an
evolution which adds reflection and conceptual thought to a mental
framework derived from prehuman ancestors. The insect hurries about in its
daily life as an animated machine, whose activities are defined by
heredity;