discoveries that are made, even by laboratory experiment, are later
disproved. Even in regard to this very valuable work of Dr. Reed and
his associates, one may feel too sure. It is quite possible that
future study will materially supplement and modify our present
knowledge of the subject. The scientist, therefore, may well assume an
attitude of doubt toward all the results that he achieves.

Does the same hold for the young student? Is all our knowledge more or
less doubtful, so that we should hold ourselves ready to modify our
ideas at any time? And, remembering the common tendency to become
dogmatic and unprogressive on that account, should the young student,
in particular, regard some degree of uncertainty about his facts as
the ideal state of mind for him to reach? Or would such uncertainty
too easily undermine his self-confidence and render him vacillating in
action? And should firmly fixed ideas, rather than those that are
somewhat uncertain, be regarded as his goal, so that the extent to
which he feels sure of his knowledge may be taken as one measure of
his progress? Or can it be that there are two kinds of knowledge? That
some facts are true for all time, and can be learned as absolutely
true; and that others are only probabilities and must be treated as
such? In that case, which is of the former kind, and which is of the
latter?

_8. Provision for individuality as an eighth factor in study_

The scientific investigator must determine upon his own hypotheses; he
must collect and organize his data, must judge their soundness and
trace their consequences; and he must finally decide for himself when
he has finished a task. All this requires a high degree of
intellectual independence, which is possible only through a healthy