while he justly insists, that all our evidence for any matter of fact,
which lies beyond the testimony of sense or memory, is derived entirely
from the relation of cause and effect; that we have no other idea of
this relation than that of two objects, which have been frequently
_conjoined_ together; that we have no argument to convince us, that
objects, which have, in our experience, been frequently conjoined, will
likewise, in other instances, be conjoined in the same manner; and that
nothing leads us to this inference but custom or a certain instinct of
our nature; which it is indeed difficult to resist, but which, like
other instincts, may be fallacious and deceitful. While the sceptic
insists upon these topics, he shows his force, or rather, indeed, his
own and our weakness; and seems, for the time at least, to destroy all
assurance and conviction. These arguments might be displayed at greater
length, if any durable good or benefit to society could ever be expected
to result from them.

128. For here is the chief and most confounding objection to _excessive_
scepticism, that no durable good can ever result from it; while it
remains in its full force and vigour. We need only ask such a sceptic,
_What his meaning is? And what he proposes by all these curious
researches?_ He is immediately at a loss, and knows not what to answer.
A Copernican or Ptolemaic, who supports each his different system of
astronomy, may hope to produce a conviction, which will remain constant
and durable, with his audience. A Stoic or Epicurean displays
principles, which may not be durable, but which have an effect on
conduct and behaviour. But a Pyrrhonian cannot expect, that his
philosophy will have any constant influence on the mind: or if it had,
that its influence would be beneficial to society. On the contrary, he
must acknowledge, if he will acknowledge anything, that all human life
must perish, were his principles universally and steadily to prevail.