Samuel Taylor Coleridge, Biographia Literaria, or Biographical Sketches of my Literary Lifie and Opinions, 2 vols. ( London: Rest, Fenner, 1817), i. 108-16.
The critique of Hartley is developed in the fifth `and sixth chapter of Biographia Literaria, and it places a critical exploration of associationism at the centre of Coleridge's aesthetic theory. Chapter 5 briefly traces the history of 'the law of association' as a central aspect of theories of consciousness from Aristotle to David Hartley's Observations on Man, his Frame, Duty and Expectations ( 1749), dividing mental experience into three types, the active, the passive, and between them, the spontaneous. This extract is from the beginning of chapter 6.
According to [ Hartley's] system the idea or vibration a from the external object A becomes associable with the idea or vibration m from the external object M, because the oscillation a propagated itself so as to re-produce the oscillation m. But the original impression from M was essentially different from the impression A: unless therefore different causes may produce the same effect, the vibration a could never produce the vibration m: and this therefore could never be the means by which a and m are associated. To understand this, the attentive reader need only be reminded, that the ideas are themselves, in Hartley's system, nothing more than their appropriate configurative vibrations. It is a mere delusion of the fancy to conceive the pre-existence of the ideas, in any chain of association, as so many differently colored billiard-balls in contact, so that when an object, the billiard-stick, strikes the first or white ball, the same motion propagates itself through the red, green, blue, black, &c. and sets the whole in motion. No! we must suppose the very same force, which constitutes the white ball, to constitute