ter; no necessary connection--no connection at all,
except sequence in time--can be discerned between them. Consequently,
from an examination of the former, we could not determine _a priori_,
that they must be followed by the latter, or by any other result
whatever. Our knowledge here, if knowledge it can be called, is wholly
empirical, or founded on experience. As we have seen, it is absurd to
say, that one atom of matter literally _acts_ on another. On the other
hand, in the world of mind, we are directly conscious of action, and
even of causation. All mental exertion is true action; every
determination of the will implies _effort_, or the direction and use of
power. The result to be accomplished is preconsidered, or meditated, and
therefore is known _a priori_, or before experience; the volition
succeeds, which is a true effort, or a power in action; and this, _if
the power be sufficient_, is _necessarily_ followed by the effect.
Volition is a true cause; but in a finite mind it is not always an
_adequate_ cause. If I will to shut my eyes, the effect immediately
follows as a necessary consequence. But if I will to stop the beating of
my heart, or to move a paralyzed limb, the effect does not follow,
because the power exerted is inadequate to the end proposed. The action
of the will is still _causative_, but it is _insufficient_.

It was from overlooking the distinction here made, that Hume, Kant, and
other metaphysicians were led to deny all knowledge of causation even in
the action of mind. They confounded sufficiency with efficiency, and
supposed, because the power did not always accomplish the end proposed,
that it did not tend towards it, or exert any effect upon it. As the
sufficiency of the volition can only be known _a posteriori_, or after
experience, they imagined that there could be no cause but that which is
infinite, or one which is invariably followed by the whole effect
contemplated. They overlooked the fact, that, in the consciousness of
_effort_,--as in the attempt to control the action of mind, to command
the attention, &c.,--we have direct and full evidence of _power in
action_, which is necessarily causal in its nature. The mental _nisus_
is true force, exerted with a foreknowledge of the effect to be
produced, and necessarily followed by a result,--a partial one it may
be,--but one which is a true effect, whether it answers the whole
intention, or not. Here, then, we discern that necessary connecti