science, but ultimately be fully persuaded, that it cannot exist
unless the demands here stated on which its possibility depends,
be satisfied; and, as this has never been done, that there is, as
yet, no such thing as Metaphysics. But as it can never cease to
be in demand,2 -- since the interests of common sense are
intimately interwoven with it, he must confess that a radical
reform, or rather a new birth of the science after an original
plan, are unavoidable, however men may struggle against it for a
while.

     Since the Essays of Locke and Leibniz, or rather since the
origin of metaphysics so far as we know its history, nothing has
ever happened which was more decisive to its fate than the attack
made upon it by David Hume. He threw no light on this species of
knowledge, but he certainly struck a spark from which light might
have been obtained, had it caught some inflammable substance and
had its smoldering fire been carefully nursed and developed.

     Hume started from a single but important concept in
Metaphysics, viz., that of Cause and Effect (including its
derivatives force and action, etc.). He challenges reason, which
pretends to have given birth to this idea from herself, to answer
him by what right she thinks anything to be so constituted, that
if that thing be posited, something else also must necessarily be
posited; for this is the meaning of the concept of cause. He
demonstrated irrefutably that it was perfectly impossible for
reason to think a priori and by means of concepts a combination
involving necessity. We cannot at all see why, in consequence of
the existence of one thing, another must necessarily exist, or
how the concept of such a combination can arise a priori. Hence
he inferred, that reason was altogether deluded with reference to
this concept, which she erroneously considered as one of her
children, whereas in reality it was nothing but a bastard of
imagination, impregnated by experience, which subsumed certain
representations under the Law of Association, and mistook the
subjective necessity of habit for an objective necessity arising
from insight. Hence he inferred that reason had no power to think
such, combinations, even generally, because her concepts would
then be purely fictitious, and all her pretended a priori
cognitions nothing but common experiences marked with a false
stamp. In plain language there is not, and cannot be, any such
thing as metaphysics at all.3

     However hasty and mistaken Hume's conclusion may appear, it
was at least founded upon investigation, and this investigation
deserved the concentrated attention of the brighter spirits of
his day as well as determined efforts on their part to discover,
if possible, a happier solution of the problem in the sense
proposed by him, all of which would have speedily resulted in a
complete reform of the science.

     But Hume suffered the usual misfortune of metaphysicians, of
not being understood. It is positively painful to see bow utterly
his opponents, Reid, Oswald, Beattie, and lastly Priestley,
missed the point of the problem; for while they were ever taking
for granted that which he doubted, and demonstrating with zeal
and often with impudence that which he never thought of doubting,
they so misconstrued his valuable suggestion that everything
remained in its old condition, as if nothing had happened.

     The question was not whether the concept of cause was right,
useful, and even indispensable for our knowledge of nature, for
this Hume had never doubted; but whether that concept could be
thought by reason a priori, and consequently whether it possessed
an inner truth, independent of all experience, implying a wider
application than merely to the objects of experience. This was
Hume's problem. It was a question concerning the origin, not
concerning the indispensable need of the concept. Were the former
decided, the conditions of the use and the sphere of its valid
application would have been determined as a matter of course.

     But to satisfy the conditions of the problem, the opponents
of the great thinker should have penetrated very deeply into the
nature of reason, so far as it is concerned with pure thinking,-a
task which did not suit them. They found a more convenient method
of being defiant without any insight, viz., the appeal to common
sense. It is indeed a great gift of God, to possess right, or (as
they now call it) plain common sense. But this common sense must
be shown practically, by well-considered and reasonable thoughts
and words, not by appealing to it as an oracle, when no rational
justification can be advanced. To appeal to common sense, when
insight and science fail, and no sooner-this is one of the subtle
discoveries of modern times, by means of which the most
superficial ranter can safely enter the lists with the most
thorough thinker, and hold his own. But as long as a particle of
insight remains, no one would think of having recourse to this
subterfuge. For what is it but an appeal to the opinion of the
multitude, of whose applause the philosopher is ashamed, while
the popular charlatan glories and confides in it? I should think
that Hume might fairly have laid as much claim to common sense as
Beattie, and in addition to a critical reason (such as the latter
did not possess), which keeps common sense in check and prevents
it from speculating, or, if speculations are under discussion
restrains the desire to decide because it cannot satisfy itself
concerning its own arguments. By this means alone can common
sense remain sound. Chisels and hammers may suffice to work a
piece of wood, but for steel-engraving we require an engraver's
needle. Thus common sense and speculative understanding are each
serviceable in their own way, the former in judgments which apply
immediately to experience, the latter when we judge universally