The subtle body is the conjunction of the psyche with its physical base.

It is the organ of perception of the field ( in the context of gravity and electromagnetism ).

The subtle body is the way of expression of somatic unconscious in consciousness.

The interaction between perception of the field and body expression bases the work with the subtle body as one very special path to achieve the goal of human soul`s individuation:

The Union of Opposites,  the sacred marriage between the male and female, the Unus Mundus.

( Victor M. Robert )