# Sceptical Solution of These Doubts explained — An Enquiry Concerning Human Understanding > Chapter companion for An Enquiry Concerning Human Understanding by David Hume. ## What happens Hume argues that all inferences from experience are ultimately grounded in custom or habit, not reason. He explains that after observing constant conjunctions of objects (e.g., flame and heat), the mind is determined by custom to expect the one from the appearance of the other. This principle, custom, is the great guide of human life, rendering experience useful and enabling us to adjust means to ends. Hume distinguishes belief from fiction by noting that belief involves a sentiment or feeling annexed to the conception, which is not subject to the will but arises naturally from the situation of the mind. ## Themes in this chapter ### Custom and Habit as Guides Hume identifies custom as the principle that determines all inferences from experience, making it the great guide of human life and the foundation of our expectations about the future. ### Skepticism and the Limits of Human Understanding Hume argues that reason is incapable of producing inferences from experience; instead, we must rely on custom, acknowledging the narrowness of our faculties and the limits of human understanding. ### Human Nature and Uniformity Hume appeals to the uniformity of human nature, noting that the operation of custom is a natural instinct common to all humans, independent of reasoning and essential to our survival. ## Character check-ins ### Narrator The narrator presents the sceptical solution to the doubts raised in the previous chapter, arguing that custom, not reason, is the foundation of all inferences from experience. ## Key lines > 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. Habit is the fundamental principle that makes our past experiences relevant, leading us to anticipate that future events will resemble those we have observed before. _Hume emphasizes custom as the essential mechanism for applying past experience to future expectations._ > All belief of matter of fact or real existence is derived merely from some object, present to the memory or senses, and a customary conjunction between that and some other object. Every belief about facts or real things comes from a present perception (in memory or senses) combined with a habitual association between that perception and another object. _Hume summarizes his theory that belief in matters of fact is rooted in custom and present impressions._ > It follows, therefore, that the difference between fiction and belief lies in some sentiment or feeling, which is annexed to the latter, not to the former, and which depends not on the will, nor can be commanded at pleasure. The distinction between imagining something and believing it is a matter of a specific feeling that accompanies belief, a feeling that we cannot produce or suppress at will. _Hume distinguishes belief from mere imagination by appealing to a sentiment that arises naturally, not by choice._ ## Links - HTML: https://www.betterreads.online/discover/an_enquiry_concerning_human_understanding_se/chapters/v-sceptical-solution-of-these-doubts - Book: https://www.betterreads.online/discover/an_enquiry_concerning_human_understanding_se - All chapters: https://www.betterreads.online/discover/an_enquiry_concerning_human_understanding_se/chapters