"That," he replied, "is all that any definition can do. As Mill
points out, we know nothing of cause except as an antecedent--nothing
of effect except as a consequent. Of certain phenomena, one never
occurs without another, which is dissimilar: the first in point of
time we call cause, the second, effect. One who had many times seen
a rabbit pursued by a dog, and had never seen rabbits and dogs
otherwise, would think the rabbit the cause of the dog.

"But I fear," he added, laughing naturally enough, "that my rabbit is
leading me a long way from the track of my legitimate quarry: I'm
indulging in the pleasure of the chase for its own sake. What I want
you to observe is that in Herbert Spencer's definition of 'life' the
activity of a machine is included--there is nothing in the definition
that is not applicable to it. According to this sharpest of
observers and deepest of thinkers, if a man during his period of
activity is alive, so is a machine when in operation. As an inventor
and constructor of machines I know that to be true."

Moxon was silent for a long time, gazing absently into the fire. It
was growing late and I thought it time to be going, but somehow I did
not like the notion of leaving him in that isolated house, all alone
except for the presence of some person of whose nature my conjectures
could go no further than that it was unfriendly, perhaps malign.
Leaning toward him and looking earnestly into his eyes while making a
motion with my hand through the door of his workshop, I said:

"Moxon, whom have you in there?"

Somewhat to my surprise he laughed lightly and answered without