David Hume: The Criterion of Impressions and Ideas

Hume's Criterion of Determination and Empiricism

In this text, Hume, who proposed the criterion of determination without waiting for the resource that the empiricist principle provides, begins by saying...

Text 1: The Nature of Ideas and Impressions

All ideas, especially abstract ones (where the mind has very little domain or law of association of ideas), are naturally weak and obscure. The mind has but a small domain over them; they tend to be easily confused with other similar ideas. When we have used any word many times, even without giving it a precise meaning, we tend to imagine that it has a particular idea attached (though no common idea is actually located).

Instead, all impressions—that is, all feelings, whether external or internal—are strong and lively. The boundaries between them are determined more precisely, and it is not easy to fall into error or mistake regarding them (as ideas lack such precision). Therefore, if we suspect that a term is used without philosophical meaning or a corresponding idea—as happens too often—we must ask: "What impression derives from the supposed idea?" If it is impossible to allocate one, this serves to confirm our suspicion that if an idea does not correspond with a previous impression, we can say that this idea lacks a basis in experience.

Text 2: The Copy Principle and Causality

Every idea is a copy or print of some preceding feeling; where we cannot find any impression, there is certainly no idea. In all cases of unusual activity or the operation of bodies or minds, there is nothing that produces an impression—nor, consequently, can it suggest any idea of necessary connection or causality. (Nothing gives us a necessary connection, only a causal connection of experience that we know.)

However, there are many cases where a uniform object is always followed by the same fact; then, we begin to glimpse the notion of cause and connection. We then experience a new sentiment or impression: a common connection in thought or imagination between one object and its corresponding common sense. This is the origin of the idea that we seek.

The first case we observed—movement reported by the collision of two billiard balls—is just like any event that we can show at present, except that in the first instance, we could not infer one fact from another. We can do so now, after a long succession of uniform experiences. (This does not mean we already know the future, as we have not yet experienced it.)