which produces an idea, of such prodigious consequence. At first sight I
perceive, that I must not search for it in any of the particular
qualities of the objects; since. which-ever of these qualities I pitch
on, I find some object, that is not possessed of it, and yet falls under
the denomination of cause or effect. And indeed there is nothing
existent, either externally or internally, which is not to be considered
either as a cause or an effect; though it is plain there is no one quality,
which universally belongs to all beings, and gives them a title to that
denomination.

The idea, then, of causation must be derived from some relation among
objects; and that relation we must now endeavour to discover. I find in
the first place, that whatever objects are considered as causes or
effects, are contiguous; and that nothing can operate in a time or place,
which is ever so little removed from those of its existence. Though distant
objects may sometimes seem productive of each other, they are commonly
found upon examination to be linked by a chain of causes, which are
contiguous among themselves, and to the distant objects; and when in any
particular instance we cannot discover this connexion, we still presume
it to exist. We may therefore consider the relation of CONTIGUITY as
essential to that of causation; at least may suppose it such, according
to the general opinion, till we can find a more [Part IV. Sect. 5.] proper
occasion to clear up this matter, by examining what objects are or are not
susceptible of juxtaposition and conjunction.

The second relation I shall observe as essential to causes and effects,
is not so universally acknowledged, but is liable to some controversy.
It is that of PRIORITY Of time in the cause before the effect. Some
pretend that it is not absolutely necessary a cause should precede its
effect; but that any object or action, in the very first moment of its