Columbia subject headings:
Nonbeing.
Ontology--History.
Ontology.
Parmenides.
Plato.
Plato. Sophist.
Plotinus.
Harvard subject headings:
Nonbeing.
Ontology--History.
Plato. Sophist.
Princeton subject headings:
Nonbeing.
Ontology--History.
Parmenides.
Plato.
Plato. Sophist.
Plotinus.