“In the 'show' we all have: many true acquaintances and many false friends.”

Original: Nella vita, le difficoltà rivelano la vera natura delle persone, mostrandoti inoltre chi sono i veri e i falsi amici.
Source: prevale.net

Barry Mazur,
Context: Sometimes the mathematical anti-Platonist believes that headway is made by showing Platonism to be unsupportable by rational means, and that it is an incoherent position to take when formulated in a propositional vocabulary. It is easy enough to throw together propositional sentences. But it is a good deal more difficult to capture a Platonic disposition in a propositional formulation that is a full and honest expression of some flesh-and-blood mathematician’s view of things. There is, of course, no harm in trying—and maybe its a good exercise. But even if we cleverly came up with a proposition that is up to the task of expressing Platonism formally, the mere fact that the proposition cannot be demonstrated to be true won’t necessarily make it vanish. There are many things—some true, some false— unsupportable by rational means.

1840s, Past and Present (1843)

Source: The Wild Orchid: A Retelling of The Ballad of Mulan

CVI.
Caelica (1633)

An Inquiry into Meaning and Truth (1940), Introduction, p. 15
1940s
Context: Science seems to be at war with itself.... Naive realism leads to physics, and physics, if true, shows naive realism to be false. Therefore naive realism, if true, is false; therefore it is false.

Histories 16.91.5-6