ing 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
responsive. Everything may affect him. To all of the constant changes
about him he must adjust himself. He has been produced by this world,
and to live in it he must meet its every condition and change. We must,
then, look upon human nature as something coming out of the past and as
being influenced every moment by the things and forces of the present.
Man is not an independent being, unaffected by everything that happens;
on the contrary, he is affected by all influences that act upon him.
Among these influences may be mentioned weather, climate, food, and
social forces.

The condition of the various organs of a child's body determine, to some
extent, the effect which these various forces have upon it. If a child's
eyes are in any way defective, making vision poor, this tremendously
influences his life. Not only is such a child unable to see the world as
it really is, but the eyestrain resulting from poor vision has serious
effects on the child, producing all sorts of disorders. If a child
cannot hear well or is entirely deaf, many serious consequences follow.
In fact, every condition or characteristic of a child that is in any way
abnormal may lead on to other conditions and characteristics, often of a
serious nature. The growth of adenoids, for example, may lead to a
serious impairment of the mind. Poor vision may affect the whole life
and character of the individual. The influence of a parent, teacher, or
friend may determine the interest of a child and affect his whole life.
The correct view of child life is that the child is affected, in greater
or less degree, by every influence which acts upon him.

=Significance of Development and Causality.= What are the consequences of
the view just set forth? What is the significance of the facts that have
been enumerated? It is of great consequence to our thinking when we come
to recognize fully the idea of causality. We then fully accept the fact
that man's body and mind are part of a causal and orderly world.

Let us consider, for example, the movement of a muscle. Every such
movement must be caused. The physiologist has discovered what this cause
is. Ordinarily and normally, a muscle contracts only when stimulated by
a nerve current. Tiny nerve fibrils penetrate every muscle, en