[18] Thus, if a cause be defined, _that which produces any
thing;_ it is easy to observe, that _producing_ is synonimous
to _causing._ In like manner, if a cause be defined, _that by
which any thing exists;_ this is liable to the same objection.
For what is meant by these words, _by which?_ Had it been said,
that a cause is _that_ after which _any thing constantly
exists;_ we should have understood the terms. For this is,
indeed, all we know of the matter. And this constancy forms the
very essence of necessity, nor have we any other idea of it.


PART II.


75. There is no method of reasoning more common, and yet none more
blameable, than, in philosophical disputes, to endeavour the refutation
of any hypothesis, by a pretence of its dangerous consequences to
religion and morality. When any opinion leads to absurdities, it is
certainly false; but it is not certain that an opinion is false, because
it is of dangerous consequence. Such topics, therefore, ought entirely
to be forborne; as serving nothing to the discovery of truth, but only
to make the person of an antagonist odious. This I observe in general,
without pretending to draw any advantage from it. I frankly submit to
an examination of this kind, and shall venture to affirm that the
doctrines, both of necessity and of liberty, as above explained, are not
only consistent with morality, but are absolutely essential to
its support.

Necessity may be defined two ways, conformably to the two definitions of
_cause_, of which it makes an essential part. It consists either in the