“Custom, then, is the great guide of human life. It is that principle alone which renders our experience useful to us, and makes us expect, for the future, a similar train of events with those which have appeared in the past. Without the influence of custom, we should be entirely ignorant of every matter of fact beyond what is immediately present to the memory and senses. We should never know how to adjust means to ends, or to employ our natural powers in the production of any effect. There would be an end at once of all action, as well as of the chief part of speculation.” (Hume, Enquiry)
Hume is a philosopher who believes in the Copy Principle. That all ideas derive from vivid impressions, and without those impressions, the ideas fail to exist. Hume also believes that humans rely on customs and habits in order to go about their lives. The customs and habits acquired in our society allocate the expectations of “a similar train of events with those which have appeared in the past” (Hume, 200). When we get an idea from a previous impression, and a train of events follow the impression each time without fail, we build a causal relation between the impression and the events. Observing the consistency of events that succeed, we naturally begin to assume these sets of events will occur exactly, in the future. Just like this, we have already built a custom to go on. Without these customs to live by, all humans would mope about, living in their current impressions and senses of the immediate world. According to Hume, it is customs and habits that allow us to expect a future, and continue with our lives.
If customs and habits were not created, we would not know what to do with our lives. The uncertainty of what may or may not happen would drive everyone to the point of complete vegetation. Fortunately we have expectations for current and future events which allow us to go on with our daily lives. This expectation
References: Perry, Bratman and Fischer (eds.), (2010). Introduction to Philosophy: Classical and Contemporary Readings. New York: Oxford University Press Heide, D. (2013). Philosophy 100W lecture on Hume on Causation, delivered at Simon Fraser University on 16 January, 2013