The Unshakable Generation, the Children of the Light
'I turned away from the temple...'
Sethianism (or 'Classic' Gnosticism) was a Christian Gnostic spiritual tradition that first emerges into the light of history in the late 1st and early 2nd centuries A.D. (though arguably with roots stretching back further) that identified itself as firmly outside, or perhaps even against, the increasingly dominant Apostolic Christianity of the time and its growing Church. The term 'Sethian', though used by some heresiologists in Late Antiquity, is largely a modern scholarly appellation. Both Ireneus and Porphyry simply refer to this group as 'Gnostics' (Gnostikoi), while in their own religious texts a number of grandiose self-designations are used, such as 'The Unshakable Generation', 'The Seed of Seth', 'The Children of the Light' and so on. However, it should be noted that modern Gnostics following this tradition have, in large part, claimed the term 'Sethian' for themselves as a convenient identifier - much as modern Gnostics in general have claimed the term Gnosticism despite it being a wholly modern designation.
Sethian Gnostics were a loose movement, likely of independent groups sharing common texts, beliefs, and practices, rather than a centralised religion. They likely formed independent congregations entirely separate from the proto-orthodox churches that were springing up around them. The Sethian Gnostics were esoterically minded cosmological speculators and explorers of transcendent realms. For them divinity was not something to be comprehended in a purely intellectual fashion, but something to also be experienced and directly apprehended - this form of unmediated 'knowing' is what they called gnosis.
To them this relationship is what changed and transformed a Gnostic practitioner and was seen as a rebirth into the spirit - a step away from the separateness of the mortal condition and toward the transcendence of the Pleroma. Like all Gnostic schools of thought, Sethianism was syncretic in outlook and unafraid to incorporate elements from its mystical roots in the quest for divine truth and personal revelation. Sethian Gnostic roots lay predominantly in the Second Temple Judaism, Platonism, the classical Egyptian religion, and the new message of Christianity via the Gospel of John, though this should not obscure the radical and original elements at the core of the tradition.
The Sethian Gnostics remain the earliest definitively Gnostic group for which we possess a significant amount of textual evidence, appearing to both predate and form a partial source for the equally well attested Valentinian school of thought; and though likely far from complete, it is enough to reconstruct their beliefs in large part. The core doctrine or myth of Sethianism, at its most basic level, was based around their self-understanding as the spiritual descendants of Seth (a figure that was both a heavenly archetype as well as the only true born son of Adam and Eve), and a belief in a supreme triad consisting of the utterly unknowable and ineffable transcendent Father (the 'Invisible Spirit', or Monad), the divine Mother (Barbelo, Pronnoia), and the Son (Autogenes, Christ) who then emanates a group of aeons known as the 'Four Luminaries' (Harmozel, Oroiael, Daveithai, and Eleleth) who in turn emanate twelve further aeons. It is through the very last of these, Sophia (Wisdom), that the material cosmos and its authoritarian ruler (variously named as Yaldabaoth, Saklas, or Samael) is established through an act of divine error. To Sethian Gnostics it is this demiurge that has shaped the present material cosmos and set its rules in place. In doing so creating an imperfect version of the divine Fullness (Pleroma) above, of which he only ever caught but a glimpse of a reflection. This demiurge placed part of the 'light' he had taken from his mother into the first humans (Adam, Eve, and thus Seth) before trapping them and their descendents in the cycle of incarnation and rebirth into his realm, so that the light may never return to its true home in the Pleroma. The aeon Sophia repented of her mistake, calling out to the divine Fullness for help. The Pleroma responds and this then begins a sequence of further descents by various aeons culminating in the final descent of the Christ - Christos Autogenes, 'the Son', into the person of Jesus of Nazareth as the Saviour, in order to help liberate humanity through divine gnosis so that the spirit (Pneuma) within us might one day be freed and restored to its rightful place of peace and perfection
“Stop, stop, you who walk on matter. Look, I am coming down to the world of mortals for my portion that was there from the time when the innocent Sophia was conquered. She descended so that I might counter their plan, which was determined by the one who reveals himself through her.” Everyone in the house of the ignorant light was disturbed, and the abyss trembled. - The Trimorphic Protennoia (The Three Forms of the First Thought)
Sethian teachers seem to have enjoyed a considerable degree of freedom in interpreting or reinterpreting their common mythology and cosmology. As such, many minor variations on common themes can be found within their surviving corpus of work - some of which were no doubt the result of personal revelation or altered states of consciousness. The practice of Sethian Gnostics included prayer, congregational activity, rituals of meditative spiritual ascent and five-fold baptism, as well as the use of mantra-like chants. Despite their many speculations and visionary ascents the basic elements of their belief system, as described above, remained constant, and indeed are the means by which modern scholars identify a text as 'Sethian'. In their cosmologies one element that remains prominent through their entire body of literature is the figure of Barbelo - so prominent in fact that some sholars prefer the term 'Barbeloite' over 'Sethian' as a designation, and not without good reason. The aeon of Barbelo is the Second Principle of Sethianism and the very first emanation of the Father. All subsequent divine emenations in effect come through her, the divine Mother and the transcosmic 'First Thought' of the Invisible Spirit. She encompasses all potential and as such is often depicted in the androgyne as the 'Mother-Father' and even the 'Tripple-Male'. She takes a direct interest in both the plight of Sophia and the fate of her human children that remain trapped in matter, dispatching aeonic assistance (Epinnoia - divine 'afterthought', and Christ - the 'anointed'), as well as descending into the cosmos three times herself.
Various accounts of the Sethian Gnostic myth and cosmology can be found through many of their surviving holy texts, though the oldest and most foundational is found within the Apocryphon of John (the 'Secret Book' of John), which for someone interested in Sethianism or Sethian literature should always be the first port of call.
"The great Seth wrote this book with letters in one hundred and thirty years. He placed it in the mountain that is called Charaxio, in order that, at the end of the times and the eras, by the will of the divine Autogenes and the whole Pleroma, through the gift of the untraceable, unthinkable, fatherly love, it may come forth and reveal this incorruptible, holy race of the great Savior, and those who dwell with them in love, and the great, invisible, eternal Spirit, and his only-begotten Son, and the eternal light, and his great, incorruptible consort, and the incorruptible Sophia, and the Barbelon, and the whole Pleroma in eternity. Amen." - The Holy Book of the Great Invisible Spirit