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Causation
Do we ever see a cause?
One billiard ball hits another, and the second one moves. We say the first caused the second to move. Nothing seems simpler.
David Hume asked us to look closely. What do you actually see? Ball A moves. Ball A touches ball B. Ball B moves. You see one event, then another. You never see a third thing, the “necessary connection”, the push that forces B to move.
Try it · Press Play a few times. Then switch to Hume's view and look for the connection. Finally, try the counterfactual view.
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Hume concluded that causation is constant conjunction: we have seen A-then-B so many times that our mind expects B whenever A happens. The necessity is a habit of ours, not something we observe in the balls.
A modern answer, from David Lewis, is the counterfactual theory: A caused B means that if A had not happened, B would not have happened. That shifts the question to what would have happened, which leads directly to the next topic.
Key ideas
Words worth remembering
- Constant conjunction
- Events of type A are always followed by events of type B.
- Necessary connection
- The supposed force that makes an effect follow its cause.
- Counterfactual
- A claim about what would have happened if things had been different.
Think about it
If you had only ever seen one collision in your life, would you know that A caused B?