Elements of the philosophy of the human mind. By Dugald Stewart. Rev. and abridged, with critical and explanatory notes, for the use of colleges and schools. By Francis Bowen ...

216 THE INFLUENCE OF CASUAL ASSOCIATIONS.
"Ac veluti pueri trepidant, atque omnia cacis
In tenebris metuunt, sic nos in luce timemus,
Interdaum nihilo quoa sunt metuenda miagis."
Such spectres can be dispelled by the light of philosophy
only; which, by accustoming us to trace established connections,
teaches us to despise those which are casual; and, by giving a
proper direction to that bias of the mind which is the foundation
of superstition, prevents it from leading us astray.
Wrong associations may mislead even enlightened iminds. - In
the instances which we have now been considering, events come
to be combined together in the mind, merely fiom the accidental
chicurnstance of their contiguity in time, at the moment when
we perceived them. Such combinations are confined, in a great
measure, to uncultivated and unenlightened minds; or to those
individuals who, from nature or education, have a more than
ordinary facility of association. But there are other accidental
combinations, which are apt to lay hold of the most vigorous
understandings; and from which, as they are the natural and
necessary result of a limited experience, no superiority of intellect is sufficient to preserve a philosopher, in the infancy of
physical science.
As the connections among physical events are discovered to
us by experience alone, it is evident that, when we see a phenomenon preceded by a number of different circumstances, it is
impossible for us to determine, by any reasoning 5 priori, which
of these circumstances are to be regarded as the constant, and
which as the accidental, antecedents of the effect. If, in the
course of our experience, the same combination of circumstances is always exhibited to us without any alteration, and is
invariably followed by the same result, we must for ever remain
ignorant, whether this result be connected with the whole combination, or with one or more of the circumstances combined;
and therefore, if we are anxious, upon any occasion, to produce
a similar effect, the only rule that we can follow with perfect
security, is to imitate in every particular circumstance the
combination which we have seen. It is only where we have an
opportunity of separating such circumstances from each other;