nty-one
years ago, as a general outline for my classes of Medical Students, to
enable them to grasp the real problem of life, and to emphasize the Study
of Man, as basic in the Study of Medicine, the following epitome was
placed in the Preface.

"The cosmic form in which all things are created and in which all
things exist is a Universal Duality.

Involution and Evolution express the two-fold process of the One Law
of Development, corresponding to the two planes of being, the
Subjective and the Objective.

Consciousness is the central Fact of Being.

Experience is the only method of knowing.

Therefore, to Know, is to Become.

The Modulus of Nature, that is, the Pattern, after which she
everywhere builds, and the _Method_ to which she continually conforms
is an Ideal, or Archetypical Man.

The Perfect Man is the anthropomorphic God. A living, potential
Christ in every human soul.

Two natures meet on the human plane, and focalize in man.

These are the Animal Ego and the Higher Self. The one, an inheritance
from lower life. The other, an overshadowing from the next higher
plane.

The Animal Principle is Selfishness. The Divine Principle is
Altruism.

However defective in other respects human nature may be, all human
endeavor must finally be measured by the principle of Altruism and
must stand or fall by the measure in which it inspires and uplifts
Humanity.

The highest tribunal is the criterion of Truth, and the test of truth
is by its use and beneficence. 'BY THEIR WORK YE MAY KNOW THEM.'

Superstition is not Religion; Speculation is not Philosophy;
Materialism is not Science; but true religion, true philosophy and
true science are ever the handmaids of Truth, and will at last be
found in perfect harmony."

After more than twenty years of continuous and careful study since the
foregoing was written, I must still confirm and emphasize these basic
propositions to-day.

The attempt is herein made to apply them more particularly to the study of
Psychology. To add to what was then discerned and designated as "the
Modulus of Nature," an exact and comprehensive Theorem of Psychology.

I am well aware how presumptuous this would in certain quarters be
considered, if there were the least probability that "those in authority"
would read these pages at all. The motive is involved in the modulus, and
I am quite content to leave it there, while the "co