Full Idea
If the human body has once been affected by two or more bodies at the same time, when the mind afterwards imagines any of them, it will straightway remember the other also.
Gist of Idea
If the body is affected by two things together, the imagining of one will conjure up the other
Source
Baruch de Spinoza (The Ethics [1675], II Pr 18)
Book Reference
Spinoza,Benedict de: 'Ethics, Improvement of Understanding, Letters', ed/tr. Elwes,R [Dover 1955], p.100
A Reaction
Very interesting to see a great rationalist philosopher making an observation right at the heart of Hume's theory of knowledge (associationism). Clearly an associationist theory of psychology need not imply a materialist (connectionist) theory of mind.