Joseph Schumpeter

'To realise the relative validity of one's convictions and yet stand for them unflinchingly is what distinguishes a civilised man from a barbarian.’

Dat is een citaat dat nogal gemakkelijk wordt toegeschreven aan Isaiah Berlin.

Hij schreef het wel, maar niet op die manier.

In "Two concepts of liberty" staat het op deze manier:

'To realise the relative validity of one's convictions', said an admirable

writer of our time, 'and yet stand for them unflinchingly is what 

distinguishes a civilised man from a barbarian.’

De bewonderenswaardige schrijver was Joseph Schumpeter.

No more than any other political method does democracy always produce the same results or promote the same interests or ideals. Rational allegiance to it thus presupposes not only a schema of hyper-rational values but also certain states of society in which democracy can be
expected to work in ways we approve. Propositions about the working of democracy are meaningless without reference to given times, places and situations and so, of course, are anti-democratic arguments.
This after all is only obvious. It should not surprise, still less shock, anyone. For it has nothing to do with the fervor or dignity of democratic conviction in any given situation. To realize the relative validity of one’s convictions and yet stand for them unflinchingly is what distinguishes a civilized man from a barbarian.

Joseph Schumpeter, Capitalism, Socialism and Democracy, p. 243 (1943)

Joseph Schumpeter is vooral bekend van "de paradox van Schumpeter".
De paradox van Schumpeter gaat als volgt:
To realize the relative validity of one’s convictions and yet stand for them unflinchingly is what distinguishes a civilized man from a barbarian.
In de logica is deze uitspraak "waar" of "niet waar".
Gelukkig heb je in dit leven altijd de keuze tussen de leugenarij (de volledige zin is "niet waar", dus je bent een leugenaar) en de barbarij (de volledige zin is "waar", dus je realiseert je de relatieve validiteit niet).