e abstract Argument from Speculative Philosophy.
Under this head are to be included all those theories which deny
the soul to be a spiritual entity, but reduce it to an atomic
arrangement, or a dependent attribute, or a process of action.
Heracleitus held that the soul was fire: of course, when the fuel
was exhausted the fire would go out. Thales taught that it was
water: this might all evaporate away. Anaximenes affirmed that it
was air, of which all things were formed by rarefaction and
condensation: on such a supposition it could have no permanent
personal identity. Critias said it was blood: this might
degenerate and lose its nature, or be poured out on the ground.
Leucippus maintained that it was a peculiar concourse of atoms: as
these came together, so they might fly apart and there be an end
of what they formed. The followers of Aristotle asserted that it
was a fifth unknown substance, with properties of its own, unlike
those of fire, air, water, and earth. This might be mortal or
immortal: there was nothing decisive in the conception or the
defining terms to prove which it was. Accordingly, the Peripatetic
school has always been divided on the question of the immortality
of the soul, from the time of its founder's immediate disciples to
this day. It cannot be clearly shown what the mighty Stagyrite's
own opinion really was.

Speculative conceptions as to the nature of the soul like the
foregoing, when advanced as arguments to establish its proper
mortality, are destitute of force, because they are gratuitous
assumptions. They are not generalizations based on careful
induction of facts; they are only arbitrary hypotheses.
Furthermore, they are inconsistent both with the facts and
phenomena of experience. Mind cannot fairly be brought into the
category of the material elements; for it has properties and
performs functions emphatically distinguishing it from every thing
else, placing it in a rank by itself, with exclusive predicates of
its own. Can fire think? Can water will? Can air feel? Can blood
see? Can a mathematical number tell the difference between good
and evil? Can earth be jealous of a rival and loyal to a duty? Can
a ganglion solve a problem in Euclid or understand the Theodicee
of Leibnitz? It is absurd to confound things so distinct. Mind is
mind, and matter is matter; and though we are now consciously
acquainted with them only in their correlation, yet there is as
much reason for supposing that t