ΛΟΓΩΙ ΘΕΩΡΗΤΟΝ. IL PRINCIPIO DI ‘OSSERVABILITÀ TEORICA’ NELLA FILOSOFIA E NELLA SCIENZA GRECHE

The essay analyzes the occurrences, in ancient Greek texts, of the nexus λόγῳ (or διὰ λόγου) θεωρητόν, referring to entities that can be object of observation or speculation through the λόγος, as opposed to what is observable through sensation/perception (αἴσθησις). Attested with certainty for the first time in Epicurus’ Letter to Herodotus in con- nection with the theory of time, the concept, in later doxographers, is already connected to the physical theories of Democritus and Anaxagoras. Applied in various areas of ancient science anf philosophy, the principle of ‘theoretical observability’ (or ‘conceivability through logos’) will find a particularly fertile ground for development in medical thought, especially in the Hellenistic and Imperial age. Numerous are the attestations in Anonymus Londiniensis and in Galen’s corpus.