The relationship between the perspectives of the perennialist tradition of pluralistic thinking and the kind of apophaticism articulated in the patristic era by Gregory of Nyssa and in the modern era by Vladimir Lossky is examined, and parallels in Islamic thinking are noted. The kind of intuitive apprehension of divine realities associated with the ancient Greek concept of the nous is seen as central to this relationship. The perennialist distinction between esoteric and exoteric aspects of any faith tradition is examined in this context, and Lossky’s sense of the importance of antinomy is seen as significant for rejecting the kind of critique of pluralism that is based on the notion that the doctrinal statements of different faith traditions should be seen as philosophical ‘truth claims’.

It is suggested that there is an aspect of perennialist thinking that might cause hesitation before adopting religious pluralism. This is the fact that, in the perennialist perspective, it is not possible to interrogate the contemplative capacities of faith traditions other than one’s own because these are not expressible in propositional terms. Because of this, religious pluralism can only be verified eschatologically. For this reason, Philip Sherrard’s kind of pluralism becomes questionable since a kind of inclusivism may be necessary: not of the usual kind that assumes the superiority of one’s own faith tradition but the kind that acknowledges that other traditions’ ways of viewing one’s own tradition in an inclusivist way may be as valid as one’s own tradition’s way of looking at other traditions in an inclusivist way. This attitude will be what we can call ‘reciprocal inclusivism’. The methodology associated with this stance will avoid syncretism and involve using other traditions primarily to deepen appreciation of one’s own tradition.

The first chapter explores the meaning of religion - which is much broader than the belief-system of any given ecclesial communion - and also the meaning of theosis in its early historical development. Religion is considered up to the early modern age but theosis only to the end of the patristic age as the springboard for the study of later developments as they relate to religion.