But in my college days I discovered that nothing can be imagined which is too strange or incredible to have been said by some philosopher.

[Mais ayant appris dès le collège qu’on ne sauroit rien imaginer de si étrange et si peu croyable, qu’il n’ait été dit par quelqu’un des philosophes.]

René Descartes (1596-1650) French philosopher, mathematician

Discourse on Method [Discours de la méthode], Part 2 (1637) [tr. Cottingham, Stoothoff (1985)]
    (Source)

See Cicero. (Source (French)). Alternate translations:

For having learnt from the very School, That one can imagin nothing so strange or incredible, which had not been said by some one of the Philosophers.
[tr. Newcombe ed. (1649)]

But I had become aware, even so early as during my college life, that no opinion, however absurd and incredible, can be imagined, which has not been maintained by some on of the philosophers.
[tr. Veitch (1901)]

But I had been taught, even in my College days, that there is nothing imaginable so strange or so little credible that it has not been maintained by one philosopher or another.
[tr. Haldane, Ross (1911)]

One cannot conceive anything so strange and so implausible that it has not already been said by one philosopher or another.