By knowledge, I mean the assurance arising from the comparison of ideas.

By proofs, those arguments, which are derived from the relation of cause and effect, and which are entirely free from doubt and uncertainty.

By probability, that evidence, which is still attended with uncertainty.

It is this last species of reasoning, I proceed to examine.
Probability or reasoning from conjecture may be divided into two kinds, viz.

that which is founded on chance, and that which arises from causes.
We shall consider each of these in order.
The idea of cause and effect is derived from experience, which presenting us with certain objects constantly conjoined with each other, produces such a habit of surveying them in that relation, that we cannot without a sensible violence survey them iii any other.