A summary of Hume's perspective is as follows:

When we reason about matters of fact to reach new conclusions, we use cause and effect: when a dropped ball hits the ground (observation), it bounces (observation), but it does not bounce when it is not dropped (observation); therefore, the dropping of the ball causes the ball to bounce.

It is merely “supposed” that there is a causal connection allowing us to infer this cause. But this connection is not necessarily true (we can imagine a world where it is false), and it is not an empirical observation (we do not directly observe any sort of causal link). Causal connection is more akin to a guess we make from experience, when things are “constantly conjoined.”

Since we need past experience (e.g., balls that are rubber can bounce, gravity pulls things downwards, I have seen a ball bounce before, etc.) to reason about any effects of an object, all the laws of nature “are known only by experience.”

This is dissatisfying, as it boils down to saying "it happened before like that, so I expect it to happen again in the same way."

A solution to the unknowability of causal relationships:

What if the two billiard balls are not separate objects, but one object, together with the table and the person who strikes them? Therefore, there is no need for necessary connections. We simply understand the system by observing it. What we perceive as “cause” is just an observation of how the larger system works, similarly to how we would observe movement. You could expand the system to as large as is necessary (the entire observable universe). This seems natural as there is no clear objective separation between a ball and a table (only human-made distinctions).

But even in this larger system, we can not differentiate correlation-only relationships from causal relationships. However, thinking of seemingly causal relationships as properties of a larger system is a bit different from Hume’s thinking: it implies that a good description of reality truly does not contain causal relationships, where Hume believes that there may be causal relationships, but we have no way to determine them.

Is this conclusion and my reading of Hume valid?

Are these perspectives different in substance or only by the definition of what an object is?

  • 1
    Hume's perspective cannot be so neatly summarized. What he was thinking about causation is highly controversial, with three leading interpretations (reductionism, skepticism and realism), and various subinterpretations within them, see IEP. The reductionism is most commonly called "Humean" and is pretty much your 'solution':"causation... as something that exists between external objects rather than in the observer, is constituted entirely by regular succession. In the external world, causation simply is the regularity of constant conjunction."
    – Conifold
    Commented Nov 17, 2023 at 9:56
  • A ball is just a bunch of atoms/quarks/fiekds/whatever. The only entities in the universe that approaches a ball as such are us. We create objects to interact with them (I cannot drink a bunch of H20 molecules, but I can drink a glass of water). Paraphrasing Kant, the subject defines the object, so, objects are subjective constructs with which we interact. Causality is just a single aspect of such interaction.
    – RodolfoAP
    Commented Nov 17, 2023 at 12:08

2 Answers 2


I think your summary of Hume's view, regardless of how valid it is, undervalues our scientific understanding. We don't simply say the ball drops and bounces, we have ideas such as the curvature of spacetime which explains why the ball drops when released, the notion of air pressure inside the ball, the idea of elasticity, of conservation of energy, of air resistance, of atoms and molecules and the forces they exert on each other, and so on, all of which can be invoked to explain in a lot of compelling detail why the ball bounces. Admittedly there is always a degree of granularity at which you cannot 'see' cause, and each of the steps in a scientific explanation are the result of inductive reasoning, but you might ask what, really, is the problem with that?

As for your suggestion, I think that obscures rather than clarifies. You have not solved the problem of unknowability, but given up the hunt for it.

  • Right. Science is something. Just because it is not everything, doesn't mean it is nothing.
    – Scott Rowe
    Commented Nov 17, 2023 at 13:04
  • Hume would say that all of those ideas of gravity, air resistance, etc. are matters of fact known from experience. Therefore, you must justify why you believe past experience will hold.
    – BigMistake
    Commented Nov 18, 2023 at 0:21
  1. I agree with your summary of Hume's perspective of the principle of causality.

    The philosopher Karl Popper dealt with the problem under the name “problem of induction”, i.e. how to justify a general statement covering infinitely many cases from a finite set of singular experiences. He agrees with Hume that one cannot justify such a conclusion and hereby confirm the general statement.

    Popper published his solution in his book Objective Knowledge, chapter “Conjectural Knowledge: My Solution of the Problem of Induction”. His solution is the principle of falsification: Sometimes singular experiences falsify(!) a general statement. They cannot verify a general statement.

  2. I do not see how your proposal to redefine "what an object is" solves the problem of induction: How to derive a general statement from finitely many singular statemens?

    Take a simple example: Why to conclude that the sun rises tomorrow because it did so all other days?

  • I think the proposed solution might be to avoid the statements and reasoning by looking at what is, and going "Oh". Like Galileo saying that observation shows that the moon is a ball, overcoming people thinking about what Aristotle said. We know the sun won't rise tomorrow, because it has never risen, and days are illusions. It's a ball going around another ball. You go from infinite steps to zero steps, no way to get lost.
    – Scott Rowe
    Commented Nov 17, 2023 at 13:01

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