The seek of a powerful force conducted to the knowledge of the anatomy of the human body at all the levels which were susceptible to produce pleasure. The state of bliss was connected to a kind of joy or even ecstasy. In this way  it was also a path to a loss of personal identity  which is required for the liberation of the soul. So the subtle body became a way to access the soul via pleasure. The evolution created more and more complex systems which had a charnel ground symbolism. In reality, the validation of the body and the sensual as a way to achieve the liberation was also an access to the life of the soul.