Mind is the basic instrument for gaining knowledge and wisdom. Controlling its vagaries and making it flow in a concentrated manner is the best means of attaining knowledge in any field. This however is easier said than done. By a long and arduous process of yogic discipline which includes the practice of ethical principles like ahiṁsā (non-violence), satya (truth) and brahmacarya (continence) and the practice of concentration by stages, the mind loses all its dross and impurities and becomes placid and pellucid. Such a state of mind is called ‘adhyātma-prasāda’ (vide Yogasūtras 1.47). In this state the mind, being rid of all impurities that distract and disturb it, has become like a pure crystal capable of reflecting the consciousness of the puruṣa (the Self), in full measure. Such a mind can produce instant knowledge of any object towards which it is directed.