Thearidas wrote On Nature. Clement, Stromateis 5.133.1 (Stählin p. 416), quotes the Doric sentence: the beginning of beings — the beginning that is truly real — is one; for that, in the beginning, is one and only. Holger Thesleff printed it in The Pythagorean Texts of the Hellenistic Period (Åbo, 1965), p. 201 (TLG 1711.001). The Canon dates the persona to the third century BCE, not the seventh.
Clement cites him among Pythagorean witnesses to a first principle, a monad.
The fragment is that one-sentence ontology, not an archaic sage with no text.
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On the Nature of Being
Ἀπόσπασμα
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