Notes on the Basics of Hume

 

 

David Hume (1711-1776) was an influential figure in the Scottish Enlightenment who challenged traditional and rationalist notions of knowledge, causality, and ethics. Empiricists like Hume say that sensory experience is the only source of knowledge. Unlike rationalists who believe in innate ideas or truths accessible through reason alone, Hume argues that our ideas are derived from impressions, which are the immediate data of sensation or reflection.

There are two categories of human knowledge for Hume, matters of fact and relations of ideas. Relations of ideas can be known prior to experience such as mathematical principles like the Pythagorean theorem. Matters of facts, on the other hand, are only known through experience or a posteriori. Furthermore, both of these types of knowledge are derived from either sensation or reflection. Therefore, Hume’s revolutionary move was to say that all of our ideas are derived from these impressions. If you examine any idea one will find its constituent impressions as impressions go from complex to simple when broken down. Ideas are faint expressions as thinking about touching fire is just an impression of actually touching it. Furthermore, the mind’s imagination is not infinite such that it cannot imagine new things. Therefore, all our ideas come from experience.

This applies to causality as well. We only have notions of causality having observed things in the world “cause” one another but rather this causality is rather simply the noticing of the immediate succession of one occurrence immediately after the other. When the sun rises we only assume it arises tomorrow. There is nothing necessary in the fact that it will just because we have seen it done millions of times. How can an individual be sure that something is caused by another simply by observing it happening, it is only induction not causality. However, do we have any other choice as this so-called causality allows society to continue pragmatically? Pure reason only goes so far such that it cannot discover anything synthetic a priori about the external world according to Hume. One can think about the numbers 1 and 2 and observe that when added have a value of 3. However, this discovery cannot reveal anything new about the external world. Even if you manage to demonstrate something occurring a million times, it does not matter since at any future instance it only takes a single counterexample to disprove it. Therefore, induction is never determinate. We can try to say perhaps instead that something has a high probability of happening but even making generalizations involves inductions and therefore is indeterminate. Thus, probability cannot enter into Hume’s views on causation unless only referring to observed probability without making the assumption that the observed probability is close to the theoretical probability. Causality is central to many tenants of rational propositions. Therefore, Hume may discard even the notion of causality in the sense that our sequential logical thought process is indeterminate and that the conclusions drawn from reasoning are fallible. Kant attempted to synthesize the rationalist and the empiricist positions in his Critique of Pure Reason and his metaphysics is discussed in great detail elsewhere on my blog. Causality is not an empirical concept drawn from perceptions, as Hume had maintained. Rather, Kant maintained that perceptions presupposes knowledge of causality.

He also advocated moral sentimentalism which argues that ethics cannot be argued on rational grounds. He believed that beliefs and emotions were separate things, and no rational argument could compel someone to act one way or the other unless it appealed to some desire that person has. He also expounded the is–ought problem which is the idea that a statement of fact can never give rise to a prescriptive conclusion of what ought to be done. In terms of human free will he was a compatibilist. This is based on his definitions of liberty and necessity. He defines liberty as the power of an individual to act or not act according to the determinations of their will and defines necessity as the observable regularity or uniformity in the operations of nature. He argued that if our actions were not necessitated then there would be no observable pattern or regularity in how our actions relate to our internal states and external factors. If our actions lacked this necessary connection to our will, they would essentially be random occurrences and there is no such thing as chance.