Hume's Theory of Causality

Modern theories of explanation derive from Hume's thinking on causality^[Hume], which he expressed via a series of rules specifying whether a cause–effect relationship exists:

• The cause and effect must be contiguous in space and time.
• The cause must precede the effect (unless Thiotimoline^[Asimov], is involved ☺).
• The cause must be correlated with the effect.
• A given cause always produces the same effect, and a given effect can only be the result of the same cause.
• Multiple exhibitions of the same effect rely on a common property of their purported causes.
• Differences in effect result from differences in causes.
• The amplitude of the effect is proportional to the amplitude of the cause (the dose–response relationship).
• If a correlation between cause and effect is not absolute, some other cause must be contributing.

Clearly force-at-a-distance and quantum mechanics stretch the limits of these rules in explaining phenomena discovered since Hume's time. See also [Hills] for a modern update.