In the Buddhist perspective, the ego or self as ordinarily considered in Western traditions (i.e., as soul or person), is a non-self, actually a non-entity (anatta). Hence the suffering, which stems from an experience -ultimately illusory- of separation and vulnerability.
Here we have to consider two things. First, according to Mahayana Buddhism, Adi-Buddha, equivalent to Dharmakaya – the highest metaphysical, or divine, level – represents that unique Being or Divine ‘State’, pervading all manifestation as Buddha-nature; and second, the notion of the Self (Atman, derived from the Hindu Vedanta) is not only compatible with that view, but also with that of the Spirit in Christianity and in Islam.
As to the soul (metaphysics and theology), though intrinsically perfect or whole in itself (one could add: in ‘primordial man’ –the purusha or Hiranyagarbha of Hinduism)- it experiences imperfection, self-limitation, anxiety and doubt in its state of (aparent) separation -the ‘fallen state’. Being, not just potentially, a ‘focal point of the Universe’, yet it becomes, through ignorance and self-will, the subject of illusions, attachments, and passions which lead to that predicament. Its condition is thus ambivalent; it can orient itself upwards (or towards the centre) – to ‘holiness’ and integration – or downwards, pulled by its ‘lower nature’ (nafs in its lower stages, according to Sufism). The end result will be either self-denial, or self-assertion; self-giving, or ego-centeredness. Inevitably, this latter tendency, based on ignorance, can only lead to an unwanted result: dispersal, disintegration, and suffering. Alas!, on the whole, if not in principle, psychiatry is not interested in this distinction or dichotomy; but let not anything else be said about this at this point.
From the viewpoint of advaita vedanta, all of what is described in this paragraph – and what follows – pertains to the empirical, relative (ontological and epistemological) level: mithya (or vyavahara), in other words.
Furthermore, going beyond Buddhist doctrines without contradicting them, we may conclude that to be ‘possessed’ by the ego (ahamkara) at its most virulent extreme, that is, as either aggressive or defensive, is tantamount to being demented, ‘out of one’s mind’, ‘besides one’s self’. It is to be possessed by the ‘devil’, as a force underlying and encouraging the ego. The latter, however, is not unopposed, for there is a persistent battle going on ‘inside’, the ‘devil’s opponent being none other than the Spirit or Self, bearer of the true light. But what could that ‘devil’ be other than ignorance and delusion?
The battle, or warfare, takes on many forms, and the subject is all too frequently only dimly aware of what is happening, the archenemy being a master of disguise and seduction. Skirmishes, rather than open confrontation, are the rule, and often there are lulls: temporary and/or apparent armistice, appeasement, ‘negotiated peace’. None will give up though – opportunities for regeneration and reintegration or for further descent into chaos will always be there.
This battle has as its aim the possession of the ‘heart’ of man, he who is placed ‘halfway between heaven and earth’. He is indeed the field of battle –his body and his feverish or deranged mind; feverish through desire and passion, and deranged because of ignorance and stupidity. We say ‘mind’ because, in his actual condition –beginningless ignorance- man does not know his real nature, which is unsullied, pure Consciousness. The two engaging forces pull in opposite directions, one of them upwards, towards liberation, the country of light and abundance, and the other downwards, towards further enchainment, to the netherworld. The confrontation will end only when it has been decided, in Plato’s words, “which shall rule, the better or the worse” (this quote borrowed from A. K. Coomaraswamy).
All this, of course, and again, is mithya – a lie from the highest perspective, even though it appears to be so real.