In my AP Euro Class, we learned a decent bit about Enlightenment individuals. The main ones were Montesquieu, Voltaire, John Locke, Thomas Hobbes, and Mary Wollstonecraft. However, when you study philosophy, you realize that these individuals are mainly mentioned in history because of their political significance. David Hume, despite being part of this time period, was not one of the main individuals we learned about. This is because his contributions were mainly to philosophy, not to politics.
In particular, David Hume’s philosophy on the nature of causality (cause and effect) was his greatest achievement. It’s a very simple idea with a lot of significance-we cannot prove cause and effect relationships.
Think about a science experiment. We have an independent variable and a dependent variable. We change the independent variable and observe the changes in the dependent variable. From this, we conclude a cause an effect. Because we changed the independent variable, the dependent variable changed. However, Hume argues that we can only observe correlation. Because the change in the dependent variable happens at the same time as the independent variable change does not mean anything. They could either be correlated events, or they could have no connection whatsoever.
This fact is integral to the human mind because it is the way that modern science says the human mind works. For example, classical conditioning. Pavlov’s experiment, where he made dogs eat right after the sound of a bell. This created a behavior in the dogs where they would start salivating when the bell was struck. This is because the natural unconditioned response that dogs had to food was now associated also with the bell, so the dogs’ nervous systems adjusted themselves. This shows that at least in animal brains, repeated sensory input creates a pattern, and makes them expect that the pattern will always happen. This is not exactly a cause-and-effect idea, but it is very similar to Hume’s argument.
His point was that constant conjunction, two different events happening in immediate succession or at the same time, leads to a formation of an expectation in the brain. There is a neurological theory called predictive coding similar to this. It states that the brain creates a sort of mental model of the environment, and that based off of previous sensory input, it is constantly predicting the next sensory inputs that it will receive. Basically, the human brain naturally moves towards patterns.
This is important because of natural tendencies that prove problematic to us. For example, confirmation bias arises a lot because of this. If a person has a lucky item, this is often because of this confirmation bias. They are making cause and effect connections without any real reasoning to it. If a person is an athlete, and they win a few competitions with the same shoes, it does not mean the shoes are lucky, or that it had a significant impact on the athlete’s performance. Another example is the hot hand fallacy. For example, if a gambler wins 3 times in a row, he will be motivated to play more because he has a subconscious idea that the streak will continue. However, this is blatantly false, because each outcome is independent of one another. That is the hot hand fallacy.
David Hume’s ideas were very important and should be taken into consideration every time we make connections between different ideas. There are more societally practical applications of this idea, for example in economics and social sciences, but these are fallacies we can stop at any time.