Psychology should be natural, not technical. It should take the form which
is the most intelligible to the common understanding, because it has to do
with common things, which are familiar to us all. It should aim at no more
than every reflecting man knows or can easily verify for himself. When
simple and unpretentious, it is least obscured by words, least liable to
fall under the influence of Physiology or Metaphysic. It should argue, not
from exceptional, but from ordinary phenomena. It should be careful to
distinguish the higher and the lower elements of human nature, and not
allow one to be veiled in the disguise of the other, lest through the
slippery nature of language we should pass imperceptibly from good to evil,
from nature in the higher to nature in the neutral or lower sense. It
should assert consistently the unity of the human faculties, the unity of
knowledge, the unity of God and law. The difference between the will and
the affections and between the reason and the passions should also be
recognized by it.

Its sphere is supposed to be narrowed to the individual soul; but it cannot
be thus separated in fact. It goes back to the beginnings of things, to
the first growth of language and philosophy, and to the whole science of
man. There can be no truth or completeness in any study of the mind which
is confined to the individual. The nature of language, though not the
whole, is perhaps at present the most important element in our knowledge of
it. It is not impossible that some numerical laws may be found to have a
place in the relations of mind and matter, as in the rest of nature. The
old Pythagorean fancy that the soul 'is or has in it harmony' may in some
degree be realized. But the indications of such numerical harmonies are
faint; either the secret of them lies deeper than we can discover, or
nature may have rebelled against the use of them in the composition of men
and animals. It is with qualitative rather than with quantitative
differences that we are concerned in Psychology. The facts relating to the