The ultimate renunciation is when one transcends the qualities of nature and perceives the soul.
As an atheist, I struggle with this idea of “the soul”, but can find meaning if I substitute “the self” or “ultimate reality”, but perhaps this is straying too far from what Patanjali intended. Other interpretations use “supreme consciousness” or self.
Iyengar lists five stages of detachment:
1. Disengaging the senses from action
2. Keeping away from desire
3. Stilling the mind
4. Mastery of desire
5. Supreme detachment
The qualities referred to here are the gunas: sattva (luminosity or serenity), rajas (vibrance) and tamas (inertia or dormancy). Hopefully we will return to these gunas again, as I feel I do not understand them completely at present.
Iyengar describes the practice of yoga (in the wider sense, rather than just asana) as the impetus for climbing the ladder to enlightenment or samadhi. By practising detachment we can pull the ladder up behind us.
For iyengar, practising yoga can help us to free ourselves from the trappings of consciousness. I might go even further and add that we would also seek to be free from the unconscious. In psychoanalytic theory, the unconscious mind is the cause of much suffering, whether from childhood trauma or just past experience. The goal of psychoanalysis is to bring the unconscious to the fore, to see what is there, thereby freeing the mind of those forces which cause suffering. Another way of doing this is through meditation – noticing those “negative automatic thoughts” (in CBT lingo) and just letting then be, observing our reaction to them without judgement. So the yoga sutras predict the whole Western psychoanalytic and psychotherapeutic tradition!