| A greater force and vivacity in the impression naturally conveys a greater to the related idea; and it is on the degrees of force and vivacity, that the belief depends, according to the foregoing system. |
| There is a second difference, which we may frequently observe in our degrees of belief and assurance, and which never fails to take place, though disclaimed by philosophers. |
| An experiment, that is recent and fresh in the memory, affects us more than one that is in some measure obliterated; and has a superior influence on the judgment, as well as on the passions. |
| A lively impression produces more assurance than a faint one; because it has more original force to communicate to the related idea, which thereby acquires a greater force and vivacity. |
| A recent observation has a like effect; because the custom and transition is there more entire, and preserves better the original force in the communication. |
| Thus a drunkard, who has seen his companion die of a debauch, is struck with that instance for some time, and dreads a like accident for himself: But as the memory of it decays away by degrees, his former security returns, and the danger seems less certain and real. |
| I add, as a third instance of this kind, that though our reasonings from proofs and from probabilities be considerably different from each other, yet the former species of reasoning often degenerates insensibly into the latter, by nothing but the multitude of connected arguments. |
| It is certain, that when an inference is drawn immediately from an object, without any intermediate cause or effect, the conviction is much stronger, and the persuasion more lively, than when the imagination is carryed through a long chain of connected arguments, however infallible the connexion of each link may be esteemed. |
| It is from the original impression, that the vivacity of all the ideas is derived, by means of the customary transition of the imagination; and it is evident this vivacity must gradually decay in proportion to the distance, and must lose somewhat in each transition. |
| Sometimes this distance has a greater influence than even contrary experiments would have; and a man may receive a more lively conviction from a probable reasoning, which is close and immediate, than from a long chain of consequences, though just and conclusive in each part. |
| Nay it is seldom such reasonings produce any conviction; and one must have a very strong and firm imagination to preserve the evidence to the end, where it passes through so many, stages. |
| But here it may not be amiss to remark a very curious phaenomenon, which the 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. |