I admit this is all very much over my head but nevertheless fascinating. I just wanted to know if Milos would be offended if someone (AHEM, rolig) were to coin the tag Greek-out to mark pages containing this type of conversation. (So we can find them again.)
Thanks, Kind-Heartedness! I enjoy your Greek-outs. I have come across (maybe in Heidegger?) the notion of truth as "unconcealedness", and it is interesting, and seems psychologically right, to think of truth as the "opposite" of forgetting.
Yes. λάθε is the aorist imperative of the root verb λανθάνω. The original meaning of λανθάνω seems to be "to escape the notice of", which is a fascinating meaning for a verb. But it also generally has to do with becoming unknown, unseen, hiding, obscuring, and forgetting -- this last of which is where λήθη comes in, a derived noun meaning a forgetting or forgetfulness. As a proper noun Λήθη it is Lethe, the river in the underworld from which spirits drink and forget their mortal lives.
One of the greatest debates among Greek scholars is concerning the word ἀλήθεια, the adjective meaning Truth. In Greek the prefix α- is a privative, or sometimes opposition or negation; however, not all words beginning with α- are privatives. The debate is whether ἀλήθεια is in fact ἀ-λήθεια - making truth a lack of hiddenness.
In essence there really isn't enough data to make a firm statement either way. It would be a fascinating derivation if it were true, and in fact many Greek philosophers writing long after the development of the language assert it as a folk etymology. In the meantime it remains as a dissertation topic for aspiring Ph.D. students everywhere.