For more information: Head, Heart, Belly, Center,
Nine Centers, Centerline, Ground, Sky, Trauma

Subjectively, the Heart should feel
warm,
open,
soft,
permeable,
flowing,
deep,
true.

Galadriel's smile exemplifies the social engagement system.
In the depths of the Heart are all the Gurus gathered!
The Heart function has two main aspects.

First, the Heart is the closest approach of the Vortex to the infinite zero point at the Eye of the Vortex, the place of Ultimate Reality and Truth.
The center point is the theoretical point towards which the primordial streams of energy are pulled.
One could say this is the force of Cosmic Love, the original motivation, which draws the world into manifestation. So in the depths of the Heart there is Love, the true force of creation, the deepest presence of the Divine Mystery.

Secondly, the Heart is the middle area between the outward-looking Head and the inward-looking Belly.
It maintains the Relationship between outer and inner; it balances the breathing out and breathing in, the taking in and giving out.

So the Heart functions are :
Truth
The True Self, the Pearl
Love
Emotion
Desire
Motivation
Relating
Breath
Rythm
Bliss (Ananda)

In the brain, this is the Limbic system (mammalian brain); it also include the Ventral Vagal branch of the ANS.
Relationship is not only a human universal, but a mammalian universal.
This explanation follows on from the model presented on the Evolution page.
The functions of Head, Heart and Belly are derived from this model.