An Enquiry Concerning Human Understanding


Philosophy 103D


Hume argues that it is beyond human understanding to know the causes of events, even the everyday ones that ordinary people think they know. There are indeed many things of crucial importance that are beyond our thought patterns.


What we believe to be genuine information, actually rests upon our belief in matters of fact. Such beliefs can reach beyond the content of present sense‑impressions and memory, Hume held, only by appealing to presumed connections of cause and effect. But since each idea is distinct and separable from every other, there is no self‑evident relation; these connections tend to be derived from our experience of similar cases. This is not always the case however, because their connection does not always depend on experience. So the crucial question in epistemology is to ask exactly how it is possible for us to learn from experience. (Enquiry IV ii) Here, Hume supposed, the most obvious point is a negative one: causal reasoning can never be justified rationally.


In order to learn, we must suppose that our past experiences bear some relevance to present and future cases. But although we do indeed believe that the future will be like the past, the truth of that belief is not self‑evident. In fact, it is always possible for nature to change, so inferences from past to future are never rationally certain. Thus, on Hume\'s view, all beliefs in matters of fact are fundamentally non‑rational. (Enquiry V i) Consider Hume\'s example: our belief that the sun will rise tomorrow. Clearly, this is a matter of fact; it rests on our conviction that each sunrise is an effect caused by the rotation of the earth. However, our belief in that causal relation is based on past observations, and our confidence that it will continue tomorrow cannot be justified by reference to the past. Therefore, we have no rational basis for believing that the sun will rise tomorrow. Yet we do believe it! Simply because an event took place many times over in the past, this does not ensure its occurrence in the future .Hume believed that all knowledge came from experience. According to Hume, a person\'s experiences exist only in the person\'s mind. As far as he is concerned, there is a world outside of human conscience, but he did not think this could be proved.


Skepticism quite properly forbids us to speculate beyond the content of our present experience and memory, yet we find it entirely natural to believe beyond them. Hume held that these unjustifiable beliefs can be explained by reference to custom or habit. That\'s how we learn from experience. When I observe the constant conjunction of events in my experience, I grow accustomed to associating them with each other. (Enquiry V ii) Although many past cases of sunrise do not guarantee the future of nature, my experience of them does get me used to the idea and produces in me an expectation that the sun will rise again tomorrow. I cannot prove that it will, but I feel that it must. Keep in mind that the association of ideas is a powerful natural process in which separate ideas come to be joined together in the mind. Of course they can be associated with each other by rational means, as they are in the relations of ideas that constitute mathematical knowledge. Even where this is possible, Hume argued, reason is a slow and inefficient guide, while the habits acquired by much repetition can produce a powerful conviction independent of reason. Although the truth of "9 Χ 12 = 108" can be established rationally in principle, most of us actually learned it by reciting our multiplication tables. In fact, what we call relative probability is, in Hume\'s view, nothing more than a measure of the strength of conviction produced in us by our experience of regularity. Our beliefs in matters of fact, then, arise from sentiment or feeling rather than from reason.


For Hume, imagination and belief differ only in the degree of conviction with which their objects are anticipated. Although this "positive answer" may seem disappointing, Hume maintained that custom or habit is the great guide of life and the foundation of all natural science. Two possibilities have generally been