present subject suggests to us. It is evident there is no point
of ancient history, of which we can have any assurance, but by passing
through many millions of causes and effects, and through a chain of
arguments of almost an immeasurable length. Before the knowledge of the
fact coued come to the first historian, it must be conveyed through many
mouths; and after it is committed to writing, each new copy is a new
object, of which the connexion with the foregoing is known only by
experience and observation. Perhaps, therefore, it may be concluded from
the precedent reasoning, that the evidence of all ancient history must
now be lost; or at least, will be lost in time, as the chain of causes
encreases, and runs on to a greater length. But as it seems contrary to
common sense to think, that if the republic of letters, and the art of
printing continue on the same footing as at present, our posterity, even
after a thousand ages, can ever doubt if there has been such a man as
JULIUS CAESAR; this may be considered as an objection to the present
system. If belief consisted only in a certain vivacity, conveyed from an
original impression, it would decay by the length of the transition, and
must at last be utterly extinguished: And vice versa, if belief on some
occasions be not capable of such an extinction; it must be something
different from that vivacity.

Before I answer this objection I shall observe, that from this topic
there has been borrowed a very celebrated argument against the Christian
Religion; but with this difference, that the connexion betwixt each link
of the chain in human testimony has been there supposed not to go beyond
probability, and to be liable to a degree of doubt and uncertainty.
And indeed it must be confest, that in this manner of considering
the subject, (which however is not a true one) there is no history or
tradition, but what must in the end lose all its force and evidence.
Every new probability diminishes the original conviction; and however
great that conviction may be supposed, it is impossible it can subsist
under such re-iterated diminutions. This is true in general; though
we shall find [Part IV. Sect. 1.] afterwards, that there is one very
memorable exception, which is of vast consequence in the present subject
of the understanding.

Mean while to give a solution of the preceding objection upon the
supposition, that historical evidence amounts at first to an entire
proof; let us consid