Besides this, we must draw a distinction between natural and artificial
groups. The group brought together by natural causes and not by man's
contriving is generally lower in the scale of civilization when it acts
collectively than any one of its components. This is the case with a mob,
a tribe, even a municipal group. But an artificial or selected group,
where the grouping is for a purpose and has been specially effected with
that end in view may act more intelligently, and be, so far as its special
activities are concerned, more advanced in the scale of progress than its
components as individuals. There is the same difference as between a man's
hand and a delicate tool. The former is the result of physical evolution
only; the latter of evolution into which the brain of man has entered as a
factor. The tool is not as good for "all round" use as the hand; but to
accomplish its particular object it is immeasurably superior.

If, then, we are to accomplish anything by taking advantage of the very
peculiar crowd or group psychology--owing to which a collected body of men
may feel as a group and act as a group, differently from the way in which
any one of its components would feel or act--we must see that our group is
properly selected and constituted. This does not mean that we are to go
about and choose individuals, one by one, by the exercise of personal
judgment. Such a method is generally inferior and unnecessary. If we
desire to separate the fine from the coarse grains in a sand-pile we do
not set to work with a microscope to measure them, grain by grain; we use
a sieve. The sieve will not do to separate iron filings from copper
filings of exactly the same size, but here a magnet will do the business.
And so separation or selection can almost always be accomplished by
choosing an agency adapted to the conditions; and such agencies often act
automatically without the intervention of the human will. In a voluntary
association formed to accomplish a definite purpose we have a