Logos

Logos is among the richest words in Greek philosophy, meaning at once word, speech, account, reason, ratio, and ordering principle. Its philosophical career begins with Heraclitus, who used it for the hidden measure that governs the cosmos and is common to all, though most people, he said, live as if they had a private understanding and fail to heed it.

Stoic and Jewish developments

The Stoics made the Logos the rational, active principle — a kind of divine fire or breath — that pervades and directs the whole universe, with individual things containing 'seminal logoi' that shape their growth. Philo of Alexandria adapted the idea, making the Logos the divine reason through which the transcendent God creates and sustains the world, the mediator between the unknowable deity and creation, which he could call God's firstborn.

In Neoplatonism

In Neoplatonism the logoi are the formative rational principles by which Soul shapes the material world after the patterns held in Intellect — the seeds of order sown from above into the realm of becoming, the channel by which intelligible form reaches matter. Through these many strands the term passed into later religious and philosophical thought, where it took on a life of its own.

From Heraclitus to the Word

For Heraclitus the Logos is the hidden measure by which all things come to pass, common to all yet missed by most. The Stoics made it the rational fire ordering the cosmos and seeding each mind; Philo and the Christian writers reshaped it as the divine Word; and the Platonists multiplied it into the logoi, the formative reason-principles by which Soul shapes matter.