καρδία
Kardia
The heart — the deep center of the person
What it means
In the Philokalia, the heart is not primarily the organ of emotion (as in modern Western usage) or the physical organ that pumps blood. Kardia refers to the deepest center of the human person — the place where intellect, will, emotion, and body converge. It is the "inner chamber" where the real person lives, beneath the surface noise of thoughts and reactions.
Theophan the Recluse, the 19th-century Russian who translated the Philokalia, offered a characteristically practical description: "The heart is the innermost man, or spirit. Here are located self-awareness, the conscience, the idea of God and of one's complete dependence on Him, and all the eternal treasures of the spiritual life."
The heart in contemplative practice
The entire arc of the Philokalia's practical teaching can be summarized as: gather the scattered attention and bring it into the heart, then guard the heart through watchfulness and prayer.
"Guarding the heart" (phylaki kardias) is a foundational practice. It means maintaining awareness of what enters this deep center — what thoughts, what impulses, what desires. The sentinel metaphor that Hesychios uses for watchfulness is specifically about standing at the entrance to the heart, watching what tries to enter.
The "prayer of the heart" — the deepest form of the Jesus Prayer — is prayer that has descended from the mind into this center. When the teachers speak of the prayer praying itself, they're describing what happens when the words of the Jesus Prayer have taken root in the kardia and continue there without conscious effort, like the heartbeat itself.
Why it matters
The Philokalia's understanding of the heart offers a corrective to the modern tendency to split the human person into separate compartments — intellect here, emotion there, body somewhere else. In this tradition, the heart is where everything meets. Prayer that reaches the heart engages the whole person. Watchfulness that guards the heart transforms not just thoughts but actions, relationships, and the quality of daily life.