Eros in philosophy (from ancient greek ἔρως, which means love) is the life force that moves the thought and philosophy itself, acting as an intermediary between the earthly dimension and the supersensible.
Eros in Plato
The first to speak of eros was Plato, who described it in the Symposium, the mouth of Diotima as a demon restless and dissatisfied, and identified it with the philosophy taken literally as "love of knowledge."
In fact, Greek mythology, Eros was the god of love, originally envisioned as a symbol of the internal cohesion of the universe and the compelling force that pushes the elements of nature to join together.
Due to its characteristic of being the unifying principle of multiplicity, Plato made it an allegory of the dialectic, ie that mental journey back to the different degrees of knowledge, starting from the sensitive until you get the idea.
The peculiarity of eros is essentially its ambiguities, or inability to land a certain and definitive knowledge, and yet the inability to resign ignorance.
According to Plato because Eros was the son of Poros (Plenty) and Penia (Poverty): philosophy understood as eros is therefore essentially love ascensional, which aspires to absolute truth and disinterested (which is its abundance), but at the same time is forced to wander in the darkness of ignorance (their poverty).
concepts already present in Socrates' knowledge of not knowing, "as well as in other myths of Plato, for example the cave where the men are sentenced to only see the shadows of the true .
Dualism and the opposition between truth and ignorance was so experienced by Plato, but since his teacher Socrates, as a deep laceration, the source of constant restlessness and dissatisfaction. This dualism is, in hindsight, the recurring theme of all Western philosophy, of which eros is in a sense the symbol.
Eros at the Neoplatonists
Especially among Neoplatonic eros will have a particularly lucky, considering the fact that the truth of being, for them, not a simple concept impersonal, but it participates in the subject: he is animated by a tension that greedy longs to know, so that love becomes a form of knowledge. Thus for Plotinus eros is a force that drives the unconscious and unintentional philosopher towards ecstasy.
Christian Neoplatonism then joined by the end of the religious philosophy of eros agape, the first indicating a ascensional and possessive love, just the human being to the Absolute and to the abstractness of the unit, the second is the love of discensivo giver, just God who moves the world and humanity in it dispersed to rejoin him.
In the Renaissance philosophers eros and agape merge well into one concept. The theme of Eros acquires a particular focus especially in the philosophy of Marsilio Ficino: love is understood by him as an expansion of God's own universe, the cause of God "pours" in the world and produces a desire in men to return to Him is a circular process that is reflected in man, which in turn is called to be a copula mundi, image of the One from whom comes all reality (as in Cusa) that binds opposite ends of the universe itself.
In Giordano Bruno, another Renaissance philosopher, Eros becomes heroic fury and exaltation of the senses and memory, elevation of reason crossed only with the courage and heroism that the search for truth implies .