In the Yoga Sūtras, Patañjali describes the movements of the mind, called vṛttis, as the various ways consciousness becomes modified and thus obscures the clarity of the Self. These vṛttis are said to be five in number, and each can be either afflicted (kliṣṭa) or non-afflicted (akliṣṭa), depending on whether it leads toward or away from inner freedom. Together they encompass the full range of mental activity, from accurate knowing to sheer fantasy, from waking cognition to the seeming emptiness of sleep. Yoga, in this vision, is the discipline of understanding and gently restraining these fluctuations so that awareness can rest in its own nature.

The first vṛtti is **pramāṇa**, usually rendered as right knowledge or valid cognition. It refers to correct understanding that arises through direct perception, inference, or trustworthy testimony. When pramāṇa is present, the mind reflects reality as it is, without distortion, and thus serves as a relatively clear mirror. Yet even this “right knowledge” is still a movement of mind, and so it too is included among the vṛttis that must ultimately be stilled.

The second is **viparyaya**, misconception or error, where the mind takes the non-real as real or misinterprets what is actually present. Classic examples include mistaking a rope for a snake or projecting qualities onto a person or situation that are not truly there. This vṛtti reveals how easily perception can be colored by habit, fear, or desire, giving rise to a world that does not quite match what is.

The third vṛtti, **vikalpa**, is imagination or verbal delusion, knowledge based solely on words or concepts without a corresponding object in reality. Here the mind spins images, theories, and narratives that may be internally coherent yet lack any actual referent. Such conceptual constructions can be useful at times, but they also show how language can create entire inner worlds that float free of direct experience.

The fourth vṛtti is **nidrā**, sleep, described as a mental state characterized by the experience of absence—an apparent voidness or “nothingness.” Even in deep sleep, there is a subtle form of cognition, a knowing of the lack of specific content, and so Patañjali counts it among the modifications of mind. This suggests that from the standpoint of yoga, the mind is not truly at rest even when it seems to have gone dark.

The fifth and final vṛtti is **smṛti**, memory, the retention and recollection of past experiences and impressions. Through smṛti, previously experienced objects and events reappear in consciousness, shaping present perception and response. Memory thus binds past and present, and while it can guide and inform, it can also keep awareness revolving around old patterns. The yogic path invites a clear seeing of all five vṛttis so that their hold gradually loosens and a deeper, unmodified awareness can shine through.