Quote by Parmenides: “It is necessary to speak and to think what is.”

Parmenides insists that only that which genuinely exists can be a subject of coherent thought and expression. This idea reinforces his belief that non-existence is inconceivable and unspeakable, guiding us to focus our intellect solely on what is real and substantial, ignoring the illusory world of change.

In his seminal poem *On Nature*, Parmenides distinguished between the 'Way of Truth' and the 'Way of Seeming.' This directive guides the philosopher to pursue only the truth of what truly exists, dismissing the deceptive appearances of the senses.

Greek philosopher from Elea, active around 480 BCE, who argued that all change and plurality are illusions and that reality is a single, eternal, unchanging whole. His philosophical poem On Nature survives in fragments and directly influenced Plato and many later Western philosophers. He is considered the founder of ontology, the study of being itself.