existence, may exert its productive quality, and give rise to another
object or action, perfectly co-temporary with itself. But beside that
experience in most instances seems to contradict this opinion, we may
establish the relation of priority by a kind of inference or reasoning.
It is an established maxim both in natural and moral philosophy, that an
object, which exists for any time in its full perfection without
producing another, is not its sole cause; but is assisted by some other
principle, which pushes it from its state of inactivity, and makes it
exert that energy, of which it was secretly possest. Now if any cause may
be perfectly co-temporary with its effect, it is certain, according to
this maxim, that they must all of them be so; since any one of them,
which retards its operation for a single moment, exerts not itself at
that very individual time, in which it might have operated; and therefore
is no proper cause. The consequence of this would be no less than the
destruction of that succession of causes, which we observe in the world;
and indeed, the utter annihilation of time. For if one cause were
co-temporary with its effect, and this effect with its effect, and so on,
it is plain there would be no such thing as succession, and all objects
must be co-existent.

If this argument appear satisfactory, it is well. If not, I beg the reader
to allow me the same liberty, which I have used in the preceding case, of
supposing it such. For he shall find, that the affair is of no great
importance.

Having thus discovered or supposed the two relations of contiguity and
succession to be essential to causes and effects, I find I am stopt
short, and can proceed no farther in considering any single instance of
cause and effect. Motion in one body is regarded upon impulse as the
cause of motion in another. When we consider these objects with utmost