| As the belief which we have of any event, encreases or diminishes according to the number of chances or past experiments, it is to be considered as a compounded effect, of which each part arises from a proportionable number of chances or experiments. |
| Let us now join these three observations, and see what conclusion we can draw from them. |
| To every probability there is an opposite possibility. |
| This possibility is composed of parts, that are entirely of the same nature with those of the probability; and consequently have the same influence on the mind and understanding. |
| The belief, which attends the probability, is a compounded effect, and is formed by the concurrence of the several effects, which proceed from each part of the probability. |
| Since therefore each part of the probability contributes to the production of the belief, each part of the possibility must have the same influence on the opposite side; the nature of these parts being entirely the same. |
| The contrary belief, attending the possibility, implies a view of a certain object, as well as the probability does an opposite view. |
| In this particular both these degrees of belief are alike. |
| The only manner then, in which the superior number of similar component parts in the one can exert its influence, and prevail above the inferior in the other, is by producing a stronger and more lively view of its object. |
| Each part presents a particular view; and all these views uniting together produce one general view, which is fuller and more distinct by the greater number of causes or principles, from which it is derived. |
| The component parts of the probability and possibility, being alike in their nature, must produce like effects; and the likeness of their effects consists in this, that each of them presents a view of a particular object. |
| But though these parts be alike in their nature, they are very different in their quantity and number; and this difference must appear in the effect as well as the similarity. |
| Now as the view they present is in both cases full and entire, and comprehends the object in all its parts, it is impossible that in this particular there can be any difference; nor is there any thing but a superior vivacity in the probability, arising from the concurrence of a superior number of views, which can distinguish these effects. |
| Here is almost the same argument in a different light. |
| All our reasonings concerning the probability of causes are founded on the transferring of past to future. |
| The transferring of any past experiment to the future is sufficient to give us a view of the object; whether that experiment be single or combined with others of the same kind; whether it be entire, or opposed by others of a contrary kind. |
| Suppose, then, it acquires both these qualities of combination and opposition, it loses not upon that account its former power of presenting a view of the object, but only concurs with and opposes other experiments, that have a like influence. |
| A question, therefore, may arise concerning the manner both of the concurrence and opposition. |
| As to the concurrence, there is only the choice left betwixt these two hypotheses. |
| First, That the view of the object, occasioned by the transference of each past experiment, preserves itself entire, and only multiplies the number of views. |
| Or, SECONDLY, That it runs into the other similar and correspondent views, and gives them a superior degree of force and vivacity. |