December 11, 2022
Dear Nikola,

Google found it for me: 
"Der Irrsinn ist bei Einzelnen etwas Seltenes, – aber bei Gruppen, Parteien, Völkern, Zeiten die Regel."
Friedrich Nietzsche, Jenseits von Gut und Böse, Part 4; Nr. 156.
(With individuals, insanity is something rare, - but with groups, parties, nations, epochs, it is the rule) Nietzsche, Beyond Good and Evil.IV,156

Nietzsche notwithstanding, I would argue:
a) From the perspective of society, as individuals, all human beings are insane.
b) Membership in society establishes the sanity and extinguishes the uniqueness of the individual. 
c) When they are integrated into society, and only then, as they are de-individualized, do human beings appear to be sane.

To try to save myself from drowning in my own incompetence, I ask why I should not consider the mathematician which I cannot become, to belong to a herd whose members are irreparably bound by a degree of intellectual and spiritual assimilation to which I am impervious.
 
In the opening chapter of his exposition of Quantum Mechanics https://www.feynmanlectures.caltech.edu/III_01.html#Ch1-S4 Feynman explains why wave effects of large objects are imperceptible.
Please see attachments.

EJM