y very remarkably, even in the simplest manifestations of their
conscious lives. It is never safe to say without qualification: "This
child did, consequently all children must." The most we can usually
say in observing single children is: "This child did, consequently
another child may."

Speaking more positively, the following remarks may be useful to those
who have a mind to observe children:

1. In the first place, we can fix no absolute time in the history of
the child at which a certain mental process takes its rise. The
observations, now quite extensively recorded, and sometimes quoted as
showing that the first year, or the second year, etc., brings such and
such developments, tend, on the contrary, to show that such divisions
do not hold in any strict sense. Like any other organic growth, the
nervous system may develop faster under more favourable conditions, or
more slowly under less favourable; and the growth of the mind is
largely dependent upon the growth of the brain. Only in broad outline
and within very wide limits can such periods be marked off at all.

2. The possibility of the occurrence of a mental state at a particular
time must be distinguished from its necessity. The occurrence of a
single clearly observed fact is decisive only against the theory
according to which its occurrence under the given conditions may not
occur. For example, the very early adaptive movements of the infant in
receiving its food can not be due to intelligence and will; but the
case is still open as to the question what is the reason of their
presence--i.e., how much nervous development is present, how much
experience is necessary, etc. It is well to emphasize the fact that
one case may be decisive in overthrowing a theory, but the conditions
are seldom simple enough to make one case decisive in establishing a
theory.

3. It follows, however, from the principle of growth itself that the
order of development of the main mental functions is constant, and
normally free from great variations; consequently, the most fruitful
observations of children are those which show that such an act was
present _before another_. The complexity becomes finally so remarkable
that there seems to be no before or after at all in mental things; but
if the child's growth shows a stage in which any process is clearly
absent, we have at once light upon the laws of growth. For instance:
if a single case is conclusively established of a child's drawin