by Charlie Huenemann
Philosophy students are typically taught the wrong lesson from the great Scottish skeptic David Hume. The standard story goes something like this. British empiricists like Locke and Berkeley wanted to connect everything we know to what we experience through the senses. The welcome consequence of this strategy is that all the stuff we see and interact with stays known – but the spooky invisible stuff, ranging from magical spirits to substantial forms and other metaphysical clutter, all goes by the wayside. But (the story continues) Hume pointed out that this strategy ends up far more corrosive than anyone expected: for, if we hold our beliefs to what we actually experience, we shall have no knowledge of causality. We see one event, and another; but never do we experience the metaphysical glue that connects the two, and forces the second event to follow the first.
The take-away lesson is that, according to Hume, we really have no knowledge of causality, and – if we are rational – we should be completely surprised every time we strike a match. This of course seems utterly loony, and it leads to spirited classroom arguments (which by itself, I’ll allow, is a good reason to teach Hume this way). How could it possibly be right that the fully rational person would not see causality at work in the world?
Well, it isn’t; and in truth, Hume never thought it was. As he defended himself to an incredulous correspondent,
… I never asserted so absurd a Proposition as that any thing might arise without a Cause: I only maintain’d, that our Certainty of the Falsehood of that Proposition proceeded neither from Intuition [sense experience] nor Demonstration; but from another Source.
Hume wasn’t a skeptic about causality. He only maintained that the causal knowledge we have does not arise from our sense experience or from our reasoning.
What’s the difference? It turns out to be an interesting one. In the first (wrong) story, the lesson is that there is no such thing as causality. That’s certainly a bold claim, but it’s not in the least compelling. No one can take it seriously except as some kind of trivial philosophical nut to crack. In the second (correct) story, the lesson is that human knowledge is not as straightforward as philosophers would like. What we know does not boil down to rational inferences from observations and arguments. It’s more natural, more organic, than that.
