The French verb trouver (to find/think) can trace its ancestry back to the Greek word τρόπος, which means a turn, manner, style, or figure of speech. Is there any logic to this seemingly disconnected progression? I can perhaps see some kind of figurative relationship between the two. Each person's thinking is unique to them in the way that a style or manner can be. Is it this figurative description that explains the semantic shift?
The Ancient Greek word τρόπος meant originally "turn", hence various meanings like "way (to be), manner, style"... and even "way to sing/compose" like in Plato's Republic 424c μουσικῆς τρόποι "~ musical modes". The Latins created the (post classical) verb * tropare "~ invent, compose an air", lately "~ compose a poem" and finally "~ compose, invent". The word is attested in French from the tenth century (in the Saint-Léger poem, v. 100) with the meaning "~ invent, meet by chance", hence the modern meanings.
The derivation of trouver “to find” < *trobare < *tropare, supposedly meaning “to compose poetry” < tropos “rhetorical figure” can be found in many respectable etymological dictionaries, but it is semantically very difficult as far as the French meaning is concerned. Another possibility that has been considered (e.g. by Meyer-Lübke) is that trouver derives from Latin turbare “to agitate, stir up”, then specifically in the sense “to disturb the water in a fish pond”, and hence “to find” fish. I think the jury is still out.