thout grounds; it may be necessary for them so to do.
Even in this case there may be a sort of blind substitute for belief. A
man, pursued by a bear, comes to a fork in the road. He knows nothing
about either branch; one may lead to safety and one to a jungle. But he
has to choose, and choose at once; and his choice represents his bid for
safety. There is plenty of action of this sort in the world; if we would
avoid the necessity for it we must do a little preliminary investigation;
and if we can not find definitely where the roads lead, we may at least
hit upon some idea of which is the safest.

But with all our investigation we shall find that we must rely in the end
on our trust in some person; either ourselves or someone else. Even the
certainty of the mathematical formula depends on our confidence in the
sanity of our own mental processes. The man who sees the basket filled
with white pebbles must trust the accuracy of his eyesight. If he relies
for his information on what someone else told him, he must trust not only
that other's eyesight, but his memory, his veracity, his friendliness. And
yet one may be far safer in trusting another than in relying on his own
unaided powers. _Securus judicat orbis terrarum_, says the old Latin. "The
world's judgment is safe." We have learned to modify this, for we have
seen world judgments that are manifestly incorrect. The world thought the
earth was flat. It thought there were witches, and it burned them. Here
individuals simply followed one another like sheep; and all, like sheep,
went astray. But where there is a real, independent judgment on the part
of each member of a group, and all agree, that is better proof of its
correctness than most individual investigations could furnish. My watch,
of the best make and carefully regulated, indicates five o'clock, but if I
meet five friends, each of whom tells me, independently, that it is six, I
conclude that my watch is wrong. There was never a more careful scientific
investigation than that by which a French physicist thought he had
established the existence of what he called the "N ray"--examined its
properties and measured its constants. He read paper after paper before
learned bodies as his research progressed. He challenged the interest of
his brother scientists on three continents. And yet he was entirely wrong:
there never was any "N ray." The man had deceived himself. The failure of
hundreds to see as he did weighed more tha