Buddhism has assumed a variety of forms over the centuries, but basically there are two forms, the śrāvakayāna and the bodhisattvayāna, otherwise known as the Hīnayāna and the Mahāyāna. Each has its own ideal, that of the śrāvakayāna being the muni or arhant, while the ideal of the bodhisattvayāna is that of Supreme Perfect Buddhahood. Both ideals, together with the spiritual practices associated with them, are undergirded by a basic common principle without which they would be meaningless. This principle is that of karma and rebirth. Christianity and Islam teach that a man or woman has only one life, after which he or she goes to heaven or hell, or spends some time in purgatory prior to admission to heaven. Buddhism, Jainism, Sikhism, and post-Vedic Hinduism teach that a man is born and dies and is reborn again and again, the process having no perceptible beginning and ending only when, in the case of the śrāvaka, Nirvāṇa is attained or when, in the case of the bodhisattva, Supreme Perfect Buddhahood is attained.

In recent times doubts have arisen regarding karma and rebirth. It has even been questioned whether the Buddha himself taught the doctrine to his disciples. In a recent publication, Rebirth in Early Buddhism and Current Research, Bhikkhu Analayo seems to have settled the matter once and for all. ‘The doctrine of rebirth is an integral and essential component of early Buddhist thought,’ he writes, ‘and cannot be reduced to a taking over of popular notions from ancient Indian background. Tradition considers rebirth and its working mechanics to have been verified by the Buddha himself on the night of his awakening. Rebirth is also intrinsically intertwined with the different levels of awakening recognised in early Buddhist thought.’ He further writes:

The early Buddhist doctrine of rebirth does not involve a simple mind-body duality, nor does it posit an unchanging entity to be reborn. Instead, continuity during life and beyond is conceived of as a changing process of a plurality of interrelated mental and physical phenomena that operate under the overarching influence of a complex set of causes and conditions. Centrally important conditions here are one’s own intentional actions (karma) at the bodily, verbal and mental level. Operating within a wider network of conditions, karma and its fruit are not deterministic, and the time period for a deed to produce its fruit can vary greatly, such that karmic fruition can take place at a time far removed from the original deed.

By its very definition the bodhisattvayāna implies the existence of rebirth. Whatever his level of attainment may be, the bodhisattva sees himself as working towards the attainment of Buddhahood not simply in his present existence, but for aeons upon aeons of lives. One cannot, therefore, claim to follow the bodhisattva path or even to be a follower of the Mahāyāna and at the same time be unwilling to accept the reality of rebirth. Similarly, by its very nature the śrāvakayāna, too, implies the existence of rebirth. As Analayo points out, ‘Rebirth is also intrinsically intertwined with the different levels of awakening recognised in early Buddhist thought.’ Thus, the stream-entrant, who destroys the first three fetters, will be reborn no more than seven times; the once-returner, having weakened two more fetters, will be reborn only once more; and the non-returner, having destroyed those two fetters, is reborn in one of the ‘pure abodes’. As for the muni or arhant, having destroyed all ten fetters, he has attained Nirvāṇa and is reborn no more. Thus the path of the śrāvaka, like that of the bodhisattva, is unthinkable without the doctrine of rebirth.

It should not be thought, however, that the śrāvakayāna and the bodhisattvayāna are mutually exclusive in every respect. In the Ten Pāramīs the śrāvakayāna has its own version of the bodhisattva path, while many of the Mahāyāna sūtras are replete with the doctrinal formulas of the śrāvakayāna. Moreover, the śrāvakayāna’s path of generosity, ethics, meditation, and wisdom can be seen as corresponding to the six pāramitās of the bodhisattvayāna, it being necessary only to add energy and patience, both of which are in any case to be found within the śrāvakayāna tradition.

The two yānas can also be seen as complementary. This became obvious as Buddhism spread and developed, and as the two yānas sought to embody their respective spiritual ideals in human form. Thus, there appear statues and paintings of arhants and bodhisattvas. The arhants are generally depicted as elderly monks. They are shaven-headed and carry a staff, and their bearing is mindful and austere. It is evident that they have spent many years meditating in caves and jungles and that they are true individuals. Indeed, in Chinese and Tibetan art their individuality is often greatly exaggerated, even to the point of caricature. Thus we have the laughing arhant, the grimacing arhant and even the ‘mad’ arhant. The bodhisattvas, on the other hand, are generally represented as beautiful young men. They are clad in diaphanous silken garments of various colours, have jewelled diadems on their heads, and are hung about with strings of jewels, as are their no less beautiful female counterparts. A gentle smile hovers about their lips and their expression is one of compassion. It is evident that they feel for the sufferings of sentient beings and are prepared to give whatever help they can. Perhaps the best-known depiction of a bodhisattva is the painting of Padmapāṇi in one of the Ajanta caves. He holds an open blue lotus and his graceful body is bent as though he is listening to the cries that come from the world below. The more we tread this or that spiritual path, the more vivid does its spiritual ideal become, especially if we practise one of the traditional sādhanas and repeat the corresponding mantra.

Besides statues of arhants and bodhisattvas there are statues of the Buddha, some of them a hundred feet or more in height. Whether followers of the Hīnayāna or the Mahāyāna, Buddhists alike believe that ages ago the ascetic Sumedha, in the world period of the Buddha Dīpaṅkara, vowed to attain Supreme Perfect Enlightenment for the sake of all beings. This vow he eventually fulfilled in the present world period when, as the historical Siddhārtha Gautama, he achieved Supreme Perfect Enlightenment seated under the bodhi tree at what became Bodh Gaya. Thereafter he taught the way to Nirvāṇa and hundreds of men and women became arhants. He did not teach the bodhisattva path, or at least there is no record of his having done so in the scriptures of early Buddhism, the Pāramīs being a later accretion.

When talking about the goal of Buddhism, we should be careful to make it clear whether we are talking about Nirvāṇa or Supreme Perfect Enlightenment, the Buddha himself being, of course, both arhant and samyak-sambuddha, as the traditional salutation to the Three Jewels makes clear. Otherwise, people may be talking at cross-purposes.