success. When a mind of this character has laboriously and
conscientiously laid in beforehand, as M. Comte had done, an ample stock
of materials, he may be justified in thinking that he will contribute
most to the mental wealth of mankind by occupying himself solely in
working upon these, without distracting his attention by continually
taking in more matter, or keeping a communication open with other
independent intellects. The practice, therefore, may be legitimate; but
no one should adopt it without being aware of what he loses by it. He
must resign the pretension of arriving at the whole truth on the
subject, whatever it be, of his meditations. That he should effect this,
even on a narrow subject, by the mere force of his own mind, building on
the foundations of his predecessors, without aid or correction from his
contemporaries, is simply impossible. He may do eminent service by
elaborating certain sides of the truth, but he must expect to find that
there are other sides which have wholly escaped his attention. However
great his powers, everything that he can do without the aid of incessant
remindings from other thinkers, is merely provisional, and will require
a thorough revision. He ought to be aware of this, and accept it with
his eyes open, regarding himself as a pioneer, not a constructor. If he
thinks that he can contribute most towards the elements of the final
synthesis by following out his own original thoughts as far as they will
go, leaving to other thinkers, or to himself at a subsequent time, the
business of adjusting them to the thoughts by which they ought to be
accompanied, he is right in doing so. But he deludes himself if he
imagines that any conclusions he can arrive at, while he practises M.
Comte's rule of _hygiène cérébrale_, can possibly be definitive.

Neither is such a practice, in a hygienic point of view, free from the
gravest dangers to the philosopher's own mind. When once he has
persuaded himself that he can work out the final truth on any subject,