To study the self is to be introspective. It is an effort to discriminate between the true self and the contingencies of one’s mind and body. To study the self, thus, is to take a critical stance towards one’s mental life. This is the only way to understand the study of the self, for Patanjali regards the mind as a potentially confounding aspect of our embodiment that can cause confusion in our self-conception. The criticism of one’s mental life is an intrinsic feature of self-study, for in Patanjali’s view, the mind is the mirror by which the self can know itself, and also the means by which the self can confuse itself. When the mind has been stilled and made morally perfect, it acts as a mirror, reflecting the essential nature of the self back on the self, whereby the self, or the person, can abide in its own true nature. When the mind is disturbed and not constrained, the self continues to understand itself through the mind, but thereby identifies itself with extraneous, disturbing factors.

From Patanjali’s Yoga Sutra, translated and commented by Shyam Ranganathan, London: Penguin, 2008, p. 132.