How is Hume’s Skepticism Related to Reason & Causality?
Rationalism: Recall that an inductive argument is one where if the premises are true the conclusion probably will be true. With an inductive argument, we reason from specific examples to general claims about all things. Inductive reasoning has built into it the idea of causation: one effect causes another event. Within this very simple reasonable connection we typically make a demonstrative connection.
If I hit the cue ball ⃝ to strike the ⑦ ball into the corner pocket that typically is demonstrative that the cue ball ⃝ hitting the ⑦ ball has a ‘necessary’ connection (above & beyond whether or not the ⑦ ball makes it into the corner pocket). In other words, we might think inductively that the event of striking the ⃝ cue ball with a cue stick will have a necessary connection between the effect of hitting the cue ball ⃝ to cause the striking of the ⑦ ball.
As rationalists we think that the two events are necessarily connected. This connection is supplied by reason & it is part of the way we do science. If one effect is necessarily connected to its cause then we can make a basic inference that events in the past will be a good indication of future events. Okay, there’s a quick gloss on a typical way we understand causation (as a rationalist).
David Hume: With consideration for Hume’s (1711-1776) Scottish Enlightenment philosophy, we must acknowledge his epistemological affinities as unmistakably empiricist. That is to say, everything we have knowledge of we have by way of the senses. This philosophical position usually stands in conflict with rationalism (the way we know of the world is primarily rational—based on a priori reason, not by necessarily sense experience).
Enter Hume’s problem of causation. Given that philosophically Hume was an empiricist he needed to explain the way we have knowledge of the world strictly by way of the five senses. Instead of inferring a way that we acquire knowledge rationally (in an a priori way). With Hume we have a way to account for all knowledge as deriving from impressions, these are sensorial and lead to our more abstract ideas of the impressions. What is of significance here is that as a good empiricist, Hume needs to account for the way we know things by way of experience and only by way of experience. Therefore the connection between our sensorial impressions and the ideas is based solely on experience. We must have a sensorial impression of one event in order to see (hear, touch, taste, or smell) that it causes another event.
Hume’s problem with causation is such that, in a rationalistic way we typically supply the necessary connection between cause & effect without the necessary connection ever being present in the experience. Sometimes students confuse what Hume is having a problem with & often misunderstand that Hume is calling physics into question. He is not suggesting that there is an absence of force between the billiard balls striking one another, or that the force is something we make-up or illusory. He is pointing out that the force is not necessary. Because this force is not necessary for Hume, this means that the typical way in which we supply this necessity is by way of habit and not reason.
In Hume’s empirical context, when we observe two billiard balls striking one another we cannot find something, no matter how hard we look (hear, smell, touch, or taste) that looks like necessity within the action of one event causing the other. That is to say, Hume was skeptical of the necessary connection we typically make in the way we understand causation. He was skeptical of the reasoning we typically use to understand causality.
We make this type of inductive inference on a daily basis: If I hit the cue ball ⃝ to strike the ⑦ ball into the corner pocket, I habitually infer that the cue ball ⃝ hitting the ⑦ ball has a ‘necessary’ connection. This necessary connection is typically supplied by reason.
To repeat, Hume is an empiricist so he has to account for the way we know the world strictly by experience. In this way, reason for Hume is called into question because causation does not have a necessary connection found with experience alone and for Hume is demoted to habit. We are in the habit of supplying the necessary connection from one event to the other. Yet another way of saying this would be to say that when we make an inductive inference, from the specific case of something causing another event to happen, we tend to habitually infer that one event will probably be effected by the same cause time & time again. Hume’s critique is that we cannot rely on this probability as necessary. Part of the way out of Hume’s problem is to have a larger sample by which to base the probability of something happening. If we base our conclusions on a wider sample then our conclusions will likely be stronger.