Pratyahara — The Withdrawal of the Senses from Their Objects
Pratyahara (sense withdrawal) is the bridge between outer and inner yoga — the practice of withdrawing the senses from their objects so that they follow the mind inward rather than drawing it outward.
Sutras 2.54-2.55 describe the fifth limb: Pratyahara — the withdrawal of the sense organs from their respective objects, so that the senses seem to imitate the nature of the mind (chittasya svarupa anukara iva). Normally the senses are like horses that pull the chariot of attention outward toward their objects. In Pratyahara, those horses are drawn back and follow the charioteer (the mind) rather than running wild. The practical consequence (2.55): supreme mastery over the senses (parama vashyata indriyananam). Pratyahara is the transitional practice — it belongs with the outer limbs (Yamas through Asana) and the inner limbs (Dharana, Dhyana, Samadhi) simultaneously. Without Pratyahara, the mind is constantly stimulated by sensory input and cannot achieve the depth of concentration required for Dharana.
When the senses withdraw from their objects and follow the nature of the mind, that is Pratyahara.
Research on the 'attention restoration theory' (Kaplan & Kaplan) confirms that directed attention — essential for meditation — is depleted by constant sensory stimulation and restored by periods of restful attention withdrawal — providing empirical support for Pratyahara as a necessary prerequisite for deep meditation.
Yoga Sutras of Patanjali