With PARMENIDES began what is called, in more specific terms, true Philosophy. The Eleatic, and his Poem, constitute a "beacon" whose light illumined Plato and even Aristotle, and consequently all the philosophers that followed. Parmenides laid down several fundamental philosophical principles: 1. The Being as foundation of all the existent 2. The principle of identity, Being is identical to itself 3. The principle of non-contradiction 4. The principle of a-temporality or eternal present 5. An initiatory philosophical vision of an experimental order This vision was taken up by Plato and others down to Plotinus and beyond, while staying in the Classical Greek tradition.