Ease
and versatility of suggestion not infrequently connote
superficiality; to make profound and far-reaching suggestions takes
time.

It is further requisite, as already pointed out, that the analyzing
mind be free from prejudice. Thinking is continually
qualified, as we have seen, by preferences and aversions.
Every prejudice, every _a priori_ belief we have, literally
prejudges the inquiry. Whenever we are moved by a "predominant
passion," we cannot survey the facts impartially.
It is hard to think clearly and justly about people whom we
love or hate, or to estimate with precision the morality of
actions toward which we are moved by very strong impulses.
It is only the mind that remains resolutely emancipated from
the compulsions of habit and circumstances, that persists in
surveying facts as they are, letting the chips, so to speak, fall
where they will, that can be really effective in thinking. In
the physical sciences it is comparatively easy to start with no
prejudices; in social inquiries where we are bound by traditions,
loyalties, and antipathies it is much more difficult.

Not the least essential to effective thinking is persistence
and thoroughness of investigation. Since we are primarily
creatures of action, we crave definiteness and immediacy of
decision, and there is a constant temptation to rush to a
conclusion. In order to attain genuine completeness of the facts
and certainty and accuracy as to what the facts are, long,
unwavering persistence is required. There must be persistence,
moreover, not merely because of the length of time and the
amount of labor involved in the collection of data; steadiness
is required in holding in mind the end or purpose of the investigation.
Too often in inquiry into the facts of human relations,
the specific problem is forgotten and facts are collected
with an indiscriminate omnivorousness. There is in such
cases plodding, but of an unenlightened and fruitless sort.
Not only _persistency_ but _consistency_ is required. The
investigation must be steadily carried on with persistent and
unwavering reference to the specific business in hand.

Effective thinking depends further on familiarity with the
field of facts under investigation. Even the most ready and
fertile of minds, the most orderly habits of thought, are at a
loss without a store of material; that is, facts from which
suggestions may arise. And this store of materials can only
be attained through a thoro