e skill,
or in the plastic and pictorial arts of manual dexterity, import this
personal element into all artistic works, the more in proportion to the
originality of the maker and the fulness of his self-expression. In
rendering from the actual such error is unavoidable, and is practically
admitted by all who would rather see for themselves than take the
account of a witness, and prefer the original to any copy of it, though
they thereby only substitute their own error for that of the artist.
This personal error, however, is easily corrected by the consensus of
human nature.

The differences in personality go far deeper than this common liability
of humanity to mere mistakes in sight and in representation. The
isolating force that creates a solitude round every man lies in his
private experience, and results from his original faculties and the
special conditions of his environment, his acquired habits of attending
to some things rather than others open to him, the choices he has made
in the past by which his view of the world and his interest in it have
been determined. Memory, the mother of the Muses, is supreme here; a
man's memory, which is the treasury of his chosen delights in life,
characterizes him, and differentiates his work from that of others,
because he must draw on that store for his materials. Thus a man's
character, or, what is more profound, his temperament, acting in
conjunction with the memory it has built up for itself, is a controlling
force in artistic work, and modifies it in the sense that it presents
the universal truth only as it exists in his personality, in his
apprehension of it and its meaning.

Genius is this power of personality, and exists in proportion as the man
differs from the average in ways that find significant expression. This
difference may proceed along two lines. It may be aberration from normal
human nature, due to circumstances or to inherent defect or to a
thousand causes, but existing always in the form of an inward perversion
approaching disease of our nature; such types of genius are pathological
and may be neglected. It may, on the other hand, be development of
normal human nature in high power, and it then exists in the form of
inward energy, showing itself in great sensitiveness to outward things,
in mental power of comprehension, in creative force of recombination
and expression. Of genius of this last sort the leaders of the human
spirit are made. The basis of it i