or one earthworm may be formed two or
three, all of which become perfect animals, and have perception and
volition; therefore, at least, the sentient principle has this property
in common with matter, that it is divisible. Then to these difficulties
add the dependence of all the higher faculties of the mind upon the state
of the brain; remember that not only all the intellectual powers, but
even sensibility is destroyed by the pressure of a little blood upon the
cerebellum, and the difficulties increase. Call to mind likewise the
suspension of animation in cases similar to that of our friend, when
there are no signs of life and when animation returns only with the
return of organic action. Surely in all these instances everything which
you consider as belonging to spirit appears in intimate dependence upon
the arrangements and properties of matter.

_The Unknown_.--The arguments you have used are those which are generally
employed by physiologists. They have weight in appearance, but not in
reality. They prove that a certain perfection of the machinery of the
body is essential to the exercise of the powers of the mind, but they do
not prove that the machine is the mind. Without the eye there can be no
sensations of vision, and without the brain there could be no recollected
visible ideas; but neither the optic nerve nor the brain can be
considered as the percipient principle--they are but the instruments of a
power which has nothing in common with them. What may be said of the
nervous system may be applied to a different part of the frame; stop the
motion of the heart, and sensibility and life cease, yet the living
principle is not in the heart, nor in the arterial blood which it sends
to every part of the system. A savage who saw the operation of a number
of power-looms weaving stockings cease at once on the stopping of the
motion of a wheel, might well imagine that the motive force was in the
wheel; he could not divine that it more immediately depended upon the
steam, and ultimately upon a fire below a concealed boiler. The
philosopher sees the fire which is the cause of the motion of this
complicated machinery, so unintelligible to the savage; but both are
equally ignorant of the divine fire which is the cause of the mechanism
of organised structures. Profoundly ignorant on this subject, all that
we can do is to give a history of our own minds. The external world or
matter is to us in fact nothing but a hea