the law of the
Degradation of Energy, which asserts that energies of a higher order are
constantly being converted into energies of a lower order. This law
maintains that energies of a lower order cannot be reconverted into
energies of a higher order. All other energies are being slowly but
surely converted into heat--the lowest of all forms of energy. And this
heat is gradually being dissipated, or radiated away, into space, so
that, at some distant day, our universe will be cold and lifeless, like
the moon.

Now it is a significant fact that the single exception to this rule
consists in, and is constituted by, _life_, or vital energy, which is
constantly building lower forms of energy into higher forms. Life is
certainly the highest form of energy which we know in this world, and
all energies are below this in rank--as may readily be proved by an
appeal to the facts of nutrition and metabolism. And, as life is
constantly being added to or infused into the world (as the population
increases), it is certainly true that there is here a definite increase
of the sum-total of the highest form of energy of which we have any
knowledge. Life thus occupies not only an important but a unique
position--in that it is constructive instead of destructive; and this
fact alone should give us pause, and make us ask whether life is, in its
totality, subject to and included within the law of Conservation of
Energy.

The establishment of the fact that the human will is a definite physical
energy is of importance also, because of its bearing upon the problem of
the connection or inter-relation of mind and matter. Theories as to this
bond or connection have been propounded since the dawn of philosophy.
Aristotle and others wrote and thought deeply upon this subject. As is
well known, this question formed one of the central points of debate in
the works of Hobbes, Berkeley, Hume, Descartes, Leibnitz, Spinoza, Kant,
Hegel, Lotze, and many other philosophical writers--all of whom wrote
and speculated at length upon this subject. The theories which have been
advanced in the past are briefly as follows:[19]

_1st. Crude Materialism._--This doctrine contends that consciousness is
merely matter, or energy, or matter in motion. It is not necessary to
discuss this theory here, as it is not held today by any scientist of
the first rank.

_2nd. Epiphenomenalism._--This doctrine found its foremost champion in
Huxley. It contends that the importan