 For Hume, the relation of causation is the only relation by means of which “we can go beyond the evidence of our memory and senses” (E. 4.1.4, T. 1.3.2.3/74). Suppose we have an object present to our senses: say gunpowder. We may then infer to an effect of that object: say, the explosion. The causal relation links our past and present experience to our expectations about the future (E. 4.1.4/26).