their objects and with one another; no less than external
bodies are connected together. The same relation, then, of cause and
effect, which belongs to one, must be common to all of them.

SECT. III. WHY A CAUSE IS ALWAYS NECESSARY.

To begin with the first question concerning the necessity of a cause:
It is a general maxim in philosophy, that whatever begins to exist, must
have a cause of existence. This is commonly taken for granted in all
reasonings, without any proof given or demanded. It is supposed to be
founded on intuition, and to be one of those maxims, which though they
may be denyed with the lips, it is impossible for men in their hearts
really to doubt of. But if we examine this maxim by the idea of
knowledge above-explained, we shall discover in it no mark of any such
intuitive certainty; but on the contrary shall find, that it is of a
nature quite foreign to that species of conviction.

All certainty arises from the comparison of ideas, and from the
discovery of such relations as are unalterable, so long as the ideas
continue the same. These relations are RESEMBLANCE, PROPORTIONS IN
QUANTITY AND NUMBER, DEGREES OF ANY QUALITY, and CONTRARIETY; none of
which are implyed in this proposition, Whatever has a beginning has
also a cause of existence. That proposition therefore is not intuitively
certain. At least any one, who would assert it to be intuitively
certain, must deny these to be the only infallible relations, and must
find some other relation of that kind to be implyed in it; which it will
then be time enough to examine.

But here is an argument, which proves at once, that the foregoing
proposition is neither intuitively nor demonstrably certain. We can
never demonstrate the necessity of a cause to every new existence, or
new modification of existence, without shewing at the same time the
impossibility there is, that any thing can ever begin to exist without
some productive principle; and where the latter proposition cannot be
proved, we must despair of ever being able to prove the former. Now that
the latter proposition is utterly incapable of a demonstrative proof,
we may satisfy ourselves by considering that as all distinct ideas are
separable from each other, and as the ideas of cause and effect are
evidently distinct, it will be easy for us to conceive any object to be
non-existent this moment, and existent the next, without conjoining to
it the distinct idea of a cause or productive p