§7. The Problem of Causation. XIV. Philosophers. Vol. 10. The Age of Johnson. The Cambridge History of English and American Literature: An Encyclopedia in Eighteen Volumes. 1907

The Cambridge History of English and American Literature in 18 Volumes (1907–21).
Volume X. The Age of Johnson.

XIV. Philosophers.

§ 7. The Problem of Causation.

This is a simple statement of the central argument of Hume’s most famous discussion. The “powers” which Locke attributed to bodies must be denied—as Berkeley denied them. The consciousness of spiritual activity on which Berkeley relied is equally illusory on Hume’s principles.

“If we reason a priori,” says Hume, “anything may appear able to produce anything. The falling of a peeble may, for aught we know, extinguish the sun, or the wish of a man control the planets in their orbits.”

This striking utterance is, strictly, little better than a truism. No philosopher ever supposed that such knowledge about definite objects could be got in any other way than by experience. But Hume’s negative criticism goes much deeper than this. We have no right to say that the extinction of the sun needs any cause at all, or that causation is a principle that holds of objects; all events are loose and separate. The only connection which we have a right to assert is that of an idea with an impression or with other ideas—the subjective routine which is called “association of ideas.” Hume’s constructive theory of causation is an explanation of how we come to suppose that there is causal connection in the world, although there is really nothing more than customary association in our minds.

If we admit Hume’s fundamental assumption about impressions and ideas, it is impossible to deny the general validity of this reasoning. Any assertion of a causal connection—the whole structure of natural science, therefore—is simply a misinterpretation of certain mental processes. At the outset, Hume himself had spoken of impressions as arising from “unknown causes”; and some expressions of the sort were necessary to give his theory a start and to carry the reader along with him; but they are really empty words. Experience is confined to impressions and ideas; causation is an attitude towards them produced by custom—by the mode of sequence of ideas; its applicability is only within the range of impressions or ideas; to talk of an impression as caused by something that is neither impression nor idea may have a very real meaning to any philosopher except Hume; but to Hume it cannot have any meaning at all.