The concept of nonself (Anatman) was central to the Buddha’s teachings to his disciples. During his prolific teaching career, he devoted countless words gestures to helping his students let go of their attachment to the search for the self’s true nature (Atman).
The orthodox philosophical schools which shaped the philosophical milieu of the Buddha’s time admitted the reality of the soul, often in terms of the soul as a representation of an absolute. The Buddha and other like-minded contemporaries took a different approach. While Mahavira and the Jains rejected the authority of the Vedas and the presence of a supreme creator, they did retain a belief in an eternal soul (the Jiva, or the Atman). The Buddha consistently discouraged his students from the soul-search and pointed to the supposed “soul” as a mere illusion as a result of grasping to the Five Aggregates.
To the Buddha, grasping to the idea of soul and its importance was a cause of suffering. To fully understand the importance of Anatman, the Atman concept should first be understood. The Buddha was reacting against the conception of the self as developed in Vedic thought. One particular book of the Vedas provides a hymn of the Cosmic Man. The Cosmic Man, or Purusha, was a primordial being whose parts became the filaments of existence. More specifically, Purusha’s cosmogonic self-sacrifice gave rise to the fourfold division of society (Varna): the Brahmins (the stewards of Vedic truth), the Ksatriyas (the rulers and warriors keeping Vedic society intact), the Vaisya (the merchants and tradesmen), and the Sudra (the laborers). Through Purusha’s sacrifice and diffusion, each person can discover their place in the cosmic whole. And, because no part can exist without the other, each part is to be treasured, understood, and effectuated. Brahman, as the causal principle underlying all things, including Purusha, is immanent in all things. If the essence of man was the atman and the essence of the universe was brahman, the principle of macrocosm-microcosm equivalence led to the famous conclusion that atman=brahman.1
As the Chandogya Upanishad put it, ‘Thou art that’; man is in essence the same as the essence of the world–not as it looks to you now but as it can be understood by the wise. […] the Buddha built upon this principle of macrocosm-microcosm equivalence, though he stood the Upanisadic conclusion on its head.” He asserted that there is no self to seek or understand.2