.
    If it be urged that the action of the potato is chemical and mechanical
only, and that it is due to the chemical and mechanical effects of light and
heat, the answer would seem to lie in an inquiry whether every sensation is not
chemical and mechanical in its operation? whether those things which we deem
most purely spiritual are anything but disturbances of equilibrium in an
infinite series of levers, beginning with those that are too small for
microscopic detection, and going up to the human arm and the appliances which it
makes use of? whether there be not a molecular action of thought, whence a
dynamical theory of the passions shall be deducible? Whether, strictly speaking,
we should not ask what kind of levers a man is made of rather than what is his
temperament? How are they balanced? How much of such and such will it take to
weigh them down so as to make him do so and so?«
    The writer went on to say that he anticipated a time when it would be
possible, by examining a single hair with a powerful microscope, to know whether
its owner could be insulted with impunity. He then became more and more obscure,
so that I was obliged to give up all attempt at translation; neither did I
follow the drift of his argument. On coming to the next part which I could
construe, I found that he had changed his ground.
    »Either,« he proceeds, »a great deal of action that has been called purely
mechanical and unconscious must be admitted to contain more elements of
consciousness than has been allowed hitherto (and in this case germs of
consciousness will be found in many actions of the higher machines) - or
(assuming the theory of evolution but at the same time denying the consciousness
of vegetable and crystalline action) the race of man has descended from things
which had no consciousness at all. In this case there is no a priori
improbability in the descent of conscious (and more than conscious) machines
from those which now exist, except that which is suggested by the apparent
absence of anything like a reproductive system in the mechanical kingdom. This
absence however is only apparent, as I shall presently show.
    Do not let me be misunderstood as living in fear of any actually existing
machine; there is probably no known machine which is more than a prototype of
future mechanical life. The present machines are to the future as the early
Saurians to man. The largest of them will probably greatly diminish in size.
Some of the lowest vertebrata attained a much greater bulk than has descended to
their more highly organized living representatives, and in like
