David Hume · Philosophy
Hume argues that we never observe a necessary connection between cause and effect - only one event constantly followed by another. Our idea of causal necessity comes not from the world but from a habit of the mind.
Cause and effect is, for Hume, the most important of all relations - the one on which nearly all our knowledge of the world beyond our immediate senses depends. Whenever we reason about matters of fact that we do not directly observe - that there is fire because we see smoke, that the bridge will hold because it held yesterday, that the medicine will cure because it has cured before - we rely on the relation of cause and effect to carry our minds from what we observe to what we do not. It is, he says, the only relation that can take us beyond the evidence of our senses and memory to genuine beliefs about the unobserved. So Hume sets out to examine it closely: what exactly is this relation of cause and effect? When we say that one thing causes another, what are we asserting, and where does the idea come from? Following his own method, he asks the decisive question: from what impression is the idea of causation - and especially the idea of necessary connection between cause and effect - derived? The answer he reaches is one of the most surprising and influential conclusions in all of philosophy.
Hume presses the point. Examine any single instance of cause and effect - one ball striking another, fire heating water, bread nourishing the body - and you will find only two things: the events are contiguous (the cause is next to the effect in space and time) and the cause is prior to the effect (it comes first). But contiguity and succession are not yet causation; many things are contiguous and successive without being cause and effect (day follows night, but does not cause it). What more is there? When Hume looks across many instances, he finds one further thing: constant conjunction. Events of the first kind have always, in our experience, been followed by events of the second kind: every time flame has touched the hand, pain has followed; every time one ball has struck another so, the second has moved. This regular, repeated, exceptionless following - the constant conjunction of the two kinds of event - is the whole of what experience gives us about causation. We never observe necessity in any single case; we observe only that, again and again, the one kind of event is followed by the other. As far as the senses can tell, that is all that ‘causation in the objects’ amounts to: not a hidden power, but a regular pattern of one thing following another.
This analysis has a radical consequence that Hume draws out unflinchingly: our causal beliefs, and indeed all our reasoning about matters of fact beyond the senses, rest not on reason but on custom or habit. Consider: why do I believe the second ball will move when struck, or that bread will nourish me tomorrow as it did today? Not because I have observed any necessary connection (I have not), and not because reason can prove it (it cannot - there is no contradiction in supposing the ball stays still or the bread poisons me). I believe it simply because I have a habit, formed by past constant conjunction, of expecting the usual effect. “Custom, then, is the great guide of human life,” Hume concludes. It is custom alone that determines us to expect the future to resemble the past, and so to draw all our practical conclusions about the world. This is not a defect to be lamented but the actual foundation of our lives: without this instinctive, habit-based expectation, we could not survive a moment, for reason alone could never justify a single prediction. Hume thus relocates the basis of our knowledge of the world from reason to human nature - from logical demonstration to the gentle, irresistible force of habit. It is one of the most profound and disquieting conclusions in philosophy: the beliefs we live by are products not of proof but of custom.
This is the opening of the lesson. The rest — the dialogue, the primary source, and the recall — is in the app.
You learned that Hume holds we never perceive a necessary connection between cause and effect, only one event regularly followed by another (constant conjunction), and that the idea of necessity comes from custom in the mind. Explain his analysis.
Leads to Immanuel Kant.
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