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 consider, that though the links are innumerable, that connect any original fact with the present impression, which is the foundation of belief; yet they are all of the same kind, and depend on the fidelity of Printers and Copyists.  One edition passes into another, and that into a third, and so on, till we come to that volume we peruse at present.  There is no variation in the steps.  After we know one we know all of them; and after we have made one, we can have no scruple as to the rest.  This circumstance alone preserves the evidence of history, and will perpetuate the memory of the present age to the latest posterity.  If all the long chain of causes and effects, which connect any past event with any volume of history, were composed of parts different from each other, and which it were necessary for the mind distinctly to conceive, it is impossible we should preserve to the end any belief or evidence.  But as most of these proofs are perfectly resembling, the mind runs easily along them, jumps from one part to another with facility, and forms but a confused and general notion of each link.  By this means a long chain of argument, has as little effect in diminishing the original vivacity, as a much shorter would have, if composed of parts, which were different from each other, and of which each required a distinct consideration.

A fourth unphilosophical species of probability is that derived from general rules, which we rashly form to ourselves, and which are the source of what we properly call prejudice.  An Irishman cannot have wit, and a Frenchman cannot have solidity; for which reason, though the conversation of the former in any instance be visibly very agreeable, and of the latter very judicious, we have entertained such a prejudice against them, that they must be dunces or fops in spite of sense and reason.  Human nature is very subject to errors of this kind; and perhaps this nation as much as any other.