this extensive authority would not be more extraordinary, nor more
beyond our comprehension. But if by consciousness we perceived any power
or energy in the will, we must know this power; we must know its
connexion with the effect; we must know the secret union of soul and
body, and the nature of both these substances; by which the one is able
to operate, in so many instances, upon the other.

_Secondly_, We are not able to move all the organs of the body with a
like authority; though we cannot assign any reason besides experience,
for so remarkable a difference between one and the other. Why has the
will an influence over the tongue and fingers, not over the heart or
liver? This question would never embarrass us, were we conscious of a
power in the former case, not in the latter. We should then perceive,
independent of experience, why the authority of will over the organs of
the body is circumscribed within such particular limits. Being in that
case fully acquainted with the power or force, by which it operates, we
should also know, why its influence reaches precisely to such
boundaries, and no farther.

A man, suddenly struck with palsy in the leg or arm, or who had newly
lost those members, frequently endeavours, at first to move them, and
employ them in their usual offices. Here he is as much conscious of
power to command such limbs, as a man in perfect health is conscious of
power to actuate any member which remains in its natural state and
condition. But consciousness never deceives. Consequently, neither in
the one case nor in the other, are we ever conscious of any power. We
learn the influence of our will from experience alone. And experience
only teaches us, how one event constantly follows another; without
instructing us in the secret connexion, which binds them together, and
renders them inseparable.