Hume argues that what most people associate as "cause" could be the constant conjunction of events. There is no way to prove a necessary connection between A and B.

However, my question has to do with whether Hume abandoned the notion of causation altogether. My understanding is that he did not but just argued it's impossible to prove A causes B.

For example, Hume argued that one cannot be held morally responsible for one's actions if they come about randomly and are not enduring (deterministic) aspects of one's personality. Therefore, in Hume's view causation exists, but we're still faced with the problem of induction.

With that being said, is it correct to say that it's still impossible to prove the notion of causation? Not only can we not show A causes B, but who's to say causation exists in the first place?

1+1=2 is true by definition and can be considered knowledge. However, is there any such argument that proves causation as well?

  • No, Hume dismissed causation as reality altogether, according to him it is an artifact of our brain associating types of events repeatedly appearing in sequence. This is a cornerstone of his associationist psychology, and a key point of Kant's disagreement with him, see Kant and Hume on Causality.
    – Conifold
    Commented Sep 18, 2018 at 19:40
  • But doesn't Hume say morality requires determinism? If our actions were entirely random and not the result of enduring personality traits how can anyone be held responsible for their actions? Last part of this video: youtube.com/watch?v=UG0IM9ErWCo. Thank you for providing an answer Geoffrey. I will read it later.
    – user27343
    Commented Sep 18, 2018 at 21:05
  • Hume does see the same causal associationism in human motives as in material bodies, and characterizes both as “constant union and conjunction of the like” with “the inference of the mind from the one to the other”. For Hume morality originates from emotions, see Hume's Moral Philosophy. That we "need" to hold people responsible is a good enough motive for us to infer causality, but it has nothing to do with whether it "exists", i.e. is real. It sure exists enough for Hume, but of course not "exists" the way you are using the word.
    – Conifold
    Commented Sep 18, 2018 at 21:39
  • Thank you that makes sense. I will refer to those sources. I guess my next question is what, if anything, does Hume refer to as "real."
    – user27343
    Commented Sep 18, 2018 at 21:44
  • Nothing really (pardon the pun), he was officially a skeptic. According to Enquiry XII.i, our belief in the reality of an external world is non-rational, it reduces neither to relations of ideas nor to matters of fact, see Hume: Empiricist Naturalism. It can be argued that he presupposes something like Berkeleyan reality of "impressions" and "ideas". But then Hume does not really care for elevating some things over others as "real" the way realists do, so it is an external reading.
    – Conifold
    Commented Sep 18, 2018 at 21:57

2 Answers 2


Hume analyses what he takes to be the ordinary concept of causation - the idea of causation that people actually use - and breaks it down into three elements : (1) temporal priority of cause to effect, (2) contiguity (closeness in space and time) of cause and effect, and (3) necessary connexion. This last means that given the cause the effect cannot but occur; the cause necessitates the effect.

Hume re-analyses the concept of causation. In this sense : he retains the temporal priority of cause to effect and the contiguity of cause and effect. But his empiricism prevents him from keeping the idea of necessary connexion. This is because he bases all knowledge ultimately on impressions - sensory perceptions. And his key contention is that not only don't we but we cannot perceive necessary connexions between events or states of affairs, or whatever we take to be the terms of the causal relation. What would it be like to perceive a necessary connexion ?

Take an example. You pour water into a kettle. You put the kettle on a lighted gas ring. The water goes from cold to lukewarm to hot to boiling. You regard this as a causal sequence of events. Hume does, too : but he asks, where in that causal sequence did you perceive necessity ? Nowhere and at no time. All you perceived was a succession of changes in the heat of the water.

So necessity has to go. Hume replaces it with 'constant conjunction' : when A-type events precede B-type events, when A- and B-type events are contiguous, and when (crucially) A-type events are regularly followed by B-type events then we say that A caused B. All that we are actually 'given' in perception are priority, contiguity, and constant conjunction (regularity of joint occurrence). We may think that A necessitates B but all that we are empirically justified in saying us that A-type events and B-type events are 'constantly conjoined', they regularly co-occur.

This 'deconstruction' of the concept of causation is quite strong enough to support claims of moral responsibility. There are two sides to this. On the one hand, if the world (or our experience of it) did not exhibit constant conjunctions then no-one would know what the consequences of their actions would be. In sceptical mood Hume doesn't believe we do know. But for the purposes of ordinary life, we 'know' that a glass will (probably) break if we drop it onto a stone floor. There is enough de facto predictability to sustain moral responsibility. This is Hume outside his study.

On the other hand, unless certain constant conjunctions held in a person's character - a key term for Hume - we could not hold that person morally responsible for anything. If given a certain belief and a certain desire, a person might form just any motive, and if with a given motive a person might form just any intention, and if with a given intention a person might do just any action, then how could they be held morally accountable for what they do ? There is no connectedness between desire, belief, motive, intention and action sufficient to sustain moral responsibility. It's because people are not like this but have a Humeanly causal mental life (packed with constant conjunctions) and act in a Humeanly causal world (equally packed with constant conjunctions), that moral responsibility is possible and real.

Hume is a determinist in the sense that he thinks that causation is pervasive but then, he doesn't think causation is anything like what we take it to be. Humean causes don't make anything happen; they simply register constant conjunctions under conditions of priority and contiguity as spelt out above.



▻ Causation

Hume, Treatise of Human Nature (1739-40), I.iii, 1-14 (esp. 14); I.iv.7.

Hume, Enquiry concerning Human Understanding (1748), IV-VII.

  • @user27343. Thank you - glad to help. I'm here to answer questions ! Best - Geoffrey
    – Geoffrey Thomas
    Commented Sep 19, 2018 at 7:34

David Hume denied the existence of cause and effect rather thoroughly. For example, Hume denied the validity of the Principle of Sufficient Reason. “For every fact F, there must be an explanation why F is the case” (Melamed and Lin 2016, §1).

In A Treatise of Human Nature, Hume considered several arguments in support of PSR, including those from Thomas Hobbes and John Locke (THN, I, 3, 3). Hume found that although this principle is said to be “impossible for men in their hearts really to doubt”, he found “no mark of any such intuitive certainty” (THN, I, 3, 3). Hume saw no merit to what Gottfeied Leibniz later called the Principle of Sufficient Reason.

[A]s all distinct ideas are separable from each other, and as the ideas of cause and effect are evidently distinct, it will be easy for us to conceive any object to be non-existent this moment, and existent the next, without conjoining to it the distinct idea of a cause or productive principle. (THN, I, 3, 3).

Hume’s denial of the Principle of Sufficient Reason destroys any possibility of causation to the next moment in time, let alone into the indefinite future.


Hume, David. A treatise of human nature http://www.gutenberg.org/files/4705/4705-h/4705-h.htm#link2H_4_0023

Melamed, Yitzhak and Lin, Martin, "Principle of Sufficient Reason", The Stanford Encyclopedia of Philosophy (Spring 2016 Edition), ed. Edward N. Zalta.

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