Two essential concepts of Plato's philosophy are brought into focus - anamnesis and truth. Anamnesis is interpreted as a mental presentation of thought that already fell into oblivion. This interpretation is brought out by linguistic analysis, as anamnesis means reverting the process of forgetting. In Plato, the immortal soul moves from the spiritual world to the corporal world and carries with itself traces of knowledge it has acquired before the incarnation. Thereafter anamnesis is provoked by signals from the sensory world, for instance, by leading questions, physical resemblance to once contemplated ideas or written text. When the soul encounters such signals, it finds in them a faint replica of what it has experienced in the spiritual world. Thereby the soul establishes contact with truth, aletheia and true beings. As alethes, truth is unforgettable, it can recede from what is immediately known but it is never entirely lost. By turning back to its own memory the soul retrieves intelligible images, foregoes the sensory world and concentrates on what precedes it. It is also a practice of renouncing the physical aspects of one's existence, and for this reason philosophy is an exercise in dying, in the separation of the soul from its mortal body.