crust--the conclusion is forced upon us that mind has passed through
many stages of development from the appearance of life upon the earth to
the present time. Among the lower forms of animals to-day one sees
evidence of very simple minds. In amoebas, worms, insects, and fishes,
mind is very simple. In birds, it is higher. In mammals, it is higher
still. Among the highest mammals below man, we see manifestations of
mind somewhat like our own. These grades of mentality shown in the
animals of to-day represent the steps in the development of mind in the
animals of the past.

We cannot here go into the proof of the doctrine of development. For
this proof, the reader must be referred to zoölogy. One further point,
however, may be noted. If it is difficult for the reader to conceive of
the development of mind on the earth similar to the development of
animals in the past, let him think of the development of mind in the
individual. There can certainly be no doubt of the development of mind
in an individual human being. The infant, when born, shows little
manifestation of mentality; but as its body grows, its mind develops,
becoming more and more complex as the individual grows to maturity.

=The World as Dynamic.= The view of the world outlined above, and held by
all scientific men of the present time, may be termed the _dynamic_
view. Man formerly looked upon the world as static, a world where
everything was fixed and final. Each thing existed in itself and for
itself, and in large measure independent of all other things. We now
look upon things and events as related and dependent. Each thing is
dependent upon others, related to others.

Man not only _lives in_ such a world, but is _part of_ such a world. In
this world of constant and ceaseless change, man is most sensitive and