In ancient Greece, the term for truth was aletheia, which is interesting because it is a negative term.
The a is a privative prefix which signifies “absence of,” and what is absent is lethe, the water of forgetfulness, which is what one drinks when one comes intoconscious existence.
When the soul is born it drinks lethe so that it forgets its prenatal life.
For the ancient Greek, truth was aletheia, meaning the absence of forgetfulness or the presence of memory.
Plato uses this term aletheia to distinguish the eternal world of forms from the phenomenal world of appearance; aletheia refers to the world of forms.
The world of appearances is only a copy or an imitation of that eternal world; aletheia is the original.
Thus Plato could say in Timaeus: “As being is to becoming, so is truth [aletheia] to belief.”
Belief is a kind of copy of truth, not the real thing. ~Edward F. Edinger, Aion Lectures, Page 128.