Karma is only a function of the physical universe, and our true energetic selves, when attracted to the lower frequencies associated with the physical universe, are linked to it. Hence the need to return to it, to break the link, to break the Karmic cycle. Once the link with the physical is broken, the need to incarnate is no longer necessary and the true energetic self can ascend the frequencies, evolving in the process without needing to experience ever again those lower frequencies associated with the physical universe.