a maxim, that the connexion between all causes and effects is
equally necessary, and that its seeming uncertainty in some
instances proceeds from the secret opposition of contrary
causes."--(IV. pp. 101-2.)

So with regard to human actions:--

"The internal principles and motives may operate in a uniform
manner, notwithstanding these seeming irregularities; in the same
manner as the winds, rains, clouds, and other variations of the
weather are supposed to be governed by steady principles; though
not easily discoverable by human sagacity and inquiry."--(IV. p.
103.)

Meteorology, as a science, was not in existence in Hume's time, or he
would have left out the "supposed to be." In practice, again, what
difference does any one make between natural and moral evidence?

"A prisoner who has neither money nor interest, discovers the
impossibility of his escape, as well when he considers the
obstinacy of the gaoler, as the walls and bars with which he is
surrounded; and, in all attempts for his freedom, chooses rather to
work upon the stone and iron of the one, than upon the inflexible
nature of the other. The same prisoner, when conducted to the
scaffold, foresees his death as certainly from the constancy and
fidelity of his guards, as from the operation of the axe or wheel.
His mind runs along a certain train of ideas: The refusal of the
soldiers to consent to his escape; the action of the executioner;
the separation of the head and body; bleeding, convulsive motions,
and death. Here is a connected chain of natural causes and
voluntary actions; but the mind feels no difference between them,
in passing from one link to another, nor is less certain of the
future event, than if it were connected with the objects presented
to the memory or senses, by a train of causes cemented together by
what we are pleased to call a _physical_ necessity. The same
experienced union has the same effect on the mind, whether the
united objects be motives, volition, and actions; or figure and
motion. We may change the names of things, but their nature and
their operation on the understanding never change."--(IV. pp.
105-6.)

But, if the necessary connexion of our acts with our ideas has always
been acknowledged in practice, why the proclivity of mankind to deny it
words?

"If we exami