e man can
reach his highest level. They become a mass with mass consciousness, a
kind of crowd in which each one becomes oversuggestible. Each one
thinks less reliably, less intelligently, and less impartially than
he would by himself alone. We know how men in a crowd do indeed lose
some of the best features of their individuality. A crowd may be
thrown into a panic, may rush into any foolish, violent action, may
lynch and plunder, or a crowd may be stirred to a pitch of enthusiasm,
may be roused to heroic deeds or to wonderful generosity, but whether
the outcome be wretched or splendid, in any case it is the product of
persons who have been entirely changed. In the midst of the panic or
in the midst of the heroic enthusiasm no one has kept his own
characteristic mental features. The individual no longer judges for
himself; he is carried away, his own heart reverberates with the
feelings of the whole crowd. The mass consciousness is not an adding
up, a mere summation, of the individual minds, but the creation of
something entirely new. Such a crowd may be pushed into any paths,
chance leaders may use or misuse its increased suggestibility for any
ends. No one can foresee whether this heaping up of men will bring
good or bad results. Certainly the individual level of the crowd will
always be below the level of its best members. And is not a jury
necessarily such a group with a mass consciousness of its own? Every
individual is melted into the total, has lost his independent power
of judging, and becomes influenced through his heightened
suggestibility and social feeling by any chance pressure which may
push toward error as often as toward truth.

But if such arguments are brought into play, it is evident that it is
no longer a legal question, but a psychological one. The psychologist
alone deals scientifically with the problem of mutual mental influence
and with the reenforcing or awakening of mental energies by social
cooeperation. He should accordingly investigate the question with his
own methods and deal with it from the standpoint of the scientist.
This means he is not simply to form an opinion from general vague
impressions and to talk about it as about a question of politics,
where any man may have his personal idea or fancy, but to discover the
facts by definite experiments. The modern student of mental life is
accustomed to the methods of the laboratory. He wants to see exact
figures by which the essential fact