“I think; therefore I am.”

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

“Travelling is almost like talking with those of other centuries.”

“Some years ago I was struck by the large number of falsehoods that I had accepted as true in my childhood, and by the highly doubtful nature of the whole edifice that I had subsequently base...”

“It is only prudent never to place complete confidence in that by which we have even once been deceived.”