"But neither can any such tablet be found in the brain, nor any style, by which to make the characters upon it; and though some of the more simple phænomena of ideas, as their being more or less deeply impressed, their being retained a longer or or a shorter time, being capable of being revived at pleasure, &c. may be pretty well explained by the hypothesis of such a tablet, and characters upon it, it is wholly inadequate to the explanation of other, and very remarkable phænomena of ideas, especially their mutual association."
— Priestley, Joseph (1733-1804)
See Hartley’s Theory of the Human Mind, on the Principle of the Association of Ideas; With Essays Relating to the Subject of It. By Joseph Priestley, LL. D. F. R. S. (London: Printed for J. Johnson, No. 72, St. Paul’s Church-Yard, 1775). <Link to ESTC>