Full Idea
Those who are ignorant of true causes make complete confusion - thinking that trees might talk just as well as men, that men might be formed from stones as well as seed, and imagine that any form might be changed into any other.
Gist of Idea
People who are ignorant of true causes imagine anything can change into anything else
Source
Baruch de Spinoza (The Ethics [1675], I Pr 08 n2)
Book Reference
Spinoza,Benedict de: 'Ethics, Improvement of Understanding, Letters', ed/tr. Elwes,R [Dover 1955], p.48
A Reaction
Spinoza himself can be guilty of this, but it strikes me as a key idea. Humean scepticism about causation seems to me the product of eighteenth century ignorance about the mechanisms of cause and effect which have since been uncovered by science.