Page:An Enquiry Concerning Human Understanding - Hume (1748).djvu/187

 that this Guide is not altogether infallible, but in some Cases is apt to lead us into Errors and Mistakes. One, who, in our Climate, should expect better Weather in any Week of June than in one of December, would reason justly and conformable to Experience; but 'tis certain, that he may happen, in the Event, to find himself mistaken. However, we may observe, that, in such a Case, he would have no Cause to complain of Experience; because it commonly informs us beforehand of the Uncertainty, by that Contrariety of Events, which we may learn from a diligent Observation. All Effects follow not with a like Certainty from their suppos'd Causes. Some Events are found, in all Countries and all Ages, to have been constantly conjoin'd together: Others are found to have been more variable, and sometimes to disappoint our Expectations; so that in our Reasonings concerning Matter of Fact, there are all imaginable Degrees of Assurance, from the highest Certainty to the lowest Species of moral Evidence.

Man, therefore, proportions his Belief to the Evidence. In such Conclusions as are founded on an infallible Experience, he expects the Event with the last Degree of Assurance, and regards his past Experience as a full Proof of the future Existence of that Event. In other Cases, he proceeds with more Caution: He weighs the opposite Experiments: He con-