Heresy (extrinsic/ intrinsic): It is once again appropriate . . . to define the difference between a heresy which is extrinsic, hence relative to a given orthodoxy, and another that is intrinsic, hence false in itself as also with respect to all orthodoxy or to Truth as such. To simplify the matter, we may limit ourselves to noting that the first type of heresy manifests a spiritual archetype – in a limited manner, no doubt, but nonetheless efficacious – whereas the second is merely human work and in consequence based solely on its own productions;* and this decides the entire question. To claim that a “pious” spiritist is assured of salvation is meaningless, for in total heresies there is no element that can guarantee posthumous beatitude^?, even though – apart from all question of belief – a man can always be saved for reasons which escape us; but he is certainly not saved by his heresy.
(* Such as Mormonism, Bahaism, the Ahmadism of Kadyan, and all the “new religions” and other pseudo-spiritualities which proliferate in today’s world.) [GTUFS: ChristIslam, The Question of Evangelicalism]

Rigorously speaking, all religious exoterism is an extrinsic heresy, evidently so with respect to other religions, but also, and above all, with respect to the sophia^? perennis; this perennial wisdom, precisely, constitutes esoterism when it is combined with a religious symbolism. An extrinsic heresy is a partial or relative truth – in its formal articulation – which presents itself as total or absolute, be it a question of religions or, within these, of denominations; but the starting point is always a truth, hence also a spiritual archetype. Altogether different is the case of an intrinsic heresy: its starting point is, either an objective error, or a subjective illusion; in the first case, the heresy lies more in the doctrine, and in the second, it is a priori^? in the pretension of the false prophet; but, needless to say, both kinds can combine, and even do so necessarily in the second case. Although there is no error possible without a particle of truth, intrinsic heresy cannot have any doctrinal or methodic value, and one cannot bring to bear on its behalf any extenuating circumstance, precisely because it projects no celestial model. [GTUFS: ChristIslam, The Question of Evangelicalism]

Heresy / Wisdom: Heresy is a form severed from its substance, hence its illegitimacy, whereas wisdom on the contrary is substance considered independently of forms, hence its universality and its imprescriptible nature. [GTUFS: FormSR, Form and Substance in the Religions]