Diogenes Laertius tells us that Diogenes wrote a Republic in which he argued that the only true state is the whole world. He proposed that currency should be abolished, that all men and women are equal citizens of the cosmos, and that the only legitimate law is natural law.
He dismissed the conventional distinctions between Greek and barbarian, free and slave. The only real distinction, he said, is between the wise and the foolish.
When asked where he came from, he said: I am a citizen of the world. He was the first to use the word cosmopolitan.
His Republic was in deliberate opposition to Plato's. Where Plato designed an ordered city governed by philosopher-kings, Diogenes imagined a world without cities at all, just individuals living according to nature, needing nothing that nature does not freely provide.
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