"It should not be thought that I have a mere analogy in mind here: we must think of the external shape of the sentient body as being really changed by the object in exactly the same way as the shape of the surface of the wax is altered by the seal."
— Descartes, René (1596-1650)
(Rule 12, p. 40)
See Opuscula posthuma, physica et mathematica (Amsterdam: P. and J. Blaeu, 1701).
Not published in Descartes' lifetime. Dutch translation in 1684; published in Latin in 1701.