In his work, Hume says that causation is the most important relation. Using the notion of causation we constantly infer some facts from facts that are actually presented to us. This is done everyday by everyone. Hume gives the example of a man finding a watch on a desert island. From this fact, he infers that the island had on one occasion been inhabited. All of our reasoning is based on this relationship between cause and effect. Thus, says Hume, is is contastantly supposed that there is a connection the inferred fact, and the fact that is presented to us. In order to validate our conclusions drawn from the cause and effect relationship we must ask ourselves how it is that we have knowledge of cause and effect.
Knowledge of cause and effect, for Hume, comes completely from experience and is in no way an a priori concept. He demonstrates this by giving the example of the first ever man, Adam. Although Adam may be gifted with perfect rationality, on observing a body of water will not be able to infer from its sensible qualities that it can suffocate him. On observing fire, Adam will not be able to infer from its sensible qualities that it will consume him. The relationship of cause and effect then must be discoverable by experience and not from a priori reasoning. That gunpowder will explode is a fact not derivable from reason but from experience.
Hume also talks about the relation of cause and effect in relation to events. On being suddenly brought into the world, then seeing one billiard ball moving towards another at rest, we fancy that we would be able to predict the result of the collision between the billiard balls. According to Hume, we would not be able to predict the result as the laws of nature come to us solely through experience. This can be demonstrated with any object. If we are given an object of which we had no previous experience then we could not determine effects it will have or indeed its cause. The mind can never discover the cause in the...