very circumstance in the cause, by which it is enabled to produce the
effect: For these are supposed to be synonimous. We must, therefore,
know both the cause and effect, and the relation between them. But do we
pretend to be acquainted with the nature of the human soul and the
nature of an idea, or the aptitude of the one to produce the other? This
is a real creation; a production of something out of nothing: Which
implies a power so great, that it may seem, at first sight, beyond the
reach of any being, less than infinite. At least it must be owned, that
such a power is not felt, nor known, nor even conceivable by the mind.
We only feel the event, namely, the existence of an idea, consequent to
a command of the will: But the manner, in which this operation is
performed, the power by which it is produced, is entirely beyond our
comprehension.

_Secondly_, The command of the mind over itself is limited, as well as
its command over the body; and these limits are not known by reason, or
any acquaintance with the nature of cause and effect, but only by
experience and observation, as in all other natural events and in the
operation of external objects. Our authority over our sentiments and
passions is much weaker than that over our ideas; and even the latter
authority is circumscribed within very narrow boundaries. Will any one
pretend to assign the ultimate reason of these boundaries, or show why
the power is deficient in one case, not in another.

_Thirdly_, This self-command is very different at different times. A man
in health possesses more of it than one languishing with sickness. We
are more master of our thoughts in the morning than in the evening:
Fasting, than after a full meal. Can we give any reason for these
variations, except experience? Where then is the power, of which we
pretend to be conscious? Is there not here, either in a spiritual or