Aletheia in its current sense comes from Heidegger's use of it as renewed attempt to understand Truth. Aletheia is the Greek word for truth, sincerity, the real or actual. It comes from a-letheia, that is unforgetful, cf, lethe. Martin Heidegger Martin Heidegger (September 26, 1889 – May 26, 1976) was a German philosopher. ... Common dictionary definitions of truth mention some form of accord with fact or reality. ... In Classical Greek, Lethe (LEE-thee) literally means forgetfulness or concealment. The Greek word for truth is a-lethe-ia, meaning un-forgetfulness or un-concealment. In Greek mythology, Lethe is one of the several rivers of Hades. ...

It does not mean truth as correspondence, ie, that something said corresponds with something in the world, with facts. Nor does it mean truth as coherence, ie, that things are true because they fit with other facts or theories. Nor truth as usefulness as in pragmatism.

Chiefly then Aletheia is the truth that first appears when something is seen or revealed. It is to take out of hiddeness to uncover. It is not something that is connected with that which appears. Allowing something appear is then the first act of truth, for example, one must give attention to something before it can be a candidate for any further understanding, for any understanding of space it must first somehow appear. Untruth then is something concealed or disguised. Space has been an interest for philosophers and scientists for much of human history, and hence it is difficult to provide an uncontroversial and clear definition outside of specific defined contexts. ...

Heidegger is trying to uncover a meaning of truth that is pre-Socratic, since Socrates, truth has instead come to mean agreement, correspondence, coherence or usefulness. ^[1] Socrates Scholasticus; for the Brazilian football player, see Sócrates (football player) Socrates Socrates (June 4, 470 – 399 BC) (Greek Σωκράτης Sōkrátēs) was a Greek (Athenian) philosopher and one of the most important icons of the Western philosophical tradition. ...