An essential doctrine in Buddhism, ānatman asserts that both the individual and objects are devoid of any permanent, unchanging essence, soul, or Self (ātman).

Because there is no subsistent reality found in or underlying appearances, there is no subsistent Self or soul in the individual. This differs from Hinduism which affirms belief in the permanent Self, ātman, underlying human appearance. For Hindus, acknowledging the Self is central for understanding the human predicament and how to escape it. Ancient Brahmanism considered ātman as a universal Self identical with brahman, the Supreme Reality. Realizing this brahman–ātman connection brings release from suffering and the process of death and rebirth.

Buddhism, on the other hand, holds that the person is constituted of five aggregates called skandhas, which in English is translatable as “heap”, “aggregate”, or “bundle”, that give the impression of identity and persistence through time, despite, as Buddhists believe, the individual having no soul within the body. 

Regardless of disagreements and debates pertaining to what the skandhas are, there is consensus that the individual is only the aggregation of components. When his truth of the non-Self is known, liberation (nirvāṇa) is made possible and attainable through total non-attachment. 

The chariot metaphor was used by Nāgasena, a Buddhist monk of the second century BCE, to illustrate the concept of ānatman. The chariot constitutes an axle, wheels, and other parts placed in a certain relation to each other. But when the parts are examined individually, it is discovered that, in an absolute sense, there is no chariot but instead just its constitutive parts. Similarly, terms such as “house”, “city”, or “tree” are, like the chariot, just modes of expression for collections of certain things arranged in a certain manner.

Where the Buddha did accept the notion of “self”, he viewed it as a particular collection of mental and physical states, which are transient rather than permanent or subsisting, despite them giving the appearance of permanence. The Buddha’s conception of non-Self challenged the Brahmanical and Jainist convictions of the day. 

An early explanation of anātman entailed the five skandhas according to which the Self is a collection of the five phenomena: form (rūpa), sensations (vedanā), perception (saṃjñā), mental formations (saṃskāras), and consciousness of the other three mental aggregates (vijñāna).

Each skandha is interdependent and constantly changing. The skandha of form entails skin constantly shedding old cells and regenerating new cells, and bones grow when the individual is young and decay when one grows older. All the skandhas are changing and shifting.

This doctrinal perspective is why Buddhism is sometimes referred to as “the teaching of no-self” (anātmavāda).