1.13 Effort toward a steady mind is practice.

“‘Effort toward steadiness’ refers to focusing and stilling the mind in meditation, to cultivation of regularity, and to developing an unwavering awareness of the mind’s activities (especially the ego’s limiting and harmful impact)…. But yoga is not limited to formal meditation or prayer…. We won’t make satisfactory progress if we practice control of the mind…

1.12 The mind can be stilled through practice and non-attachment.

“Nonattachment (vairagya) signifies the stability and serenity that arise when we withdraw from passion. The less we identify with our passions, the greater is our inner peace, in spite of difficulties. Nonattachment implies freedom with regard to affects, emotions, and sentiments…. Persevering practice is a way of proceeding, and nonattachment is what comes of it.”…

1.10 In deep sleep there is an absence of thoughts.

“Though sleep and meditation may appear the same on the outside, deep, dreamless sleep is heavy and unconscious, while deliberately meditating inwardly is alert and conscious.” –Nicolai Bachman, The Path of the Yoga Sutras

1.11 Memory is thinking about a prior experience.

“Memories create impressions in the mind and at a later time come to the surface, either when we want them or sometimes even when we do not want them.” –Sri Swami Satchidananda, The Yoga Sutras of Patanjali