The early church's authority structure, after (and even during) the apostles, was under question. Where was authority in Christian affairs to be located? Christianity was not a public cult, and had many overlapping similarities with a "philosophy", which referred not to a simple intellectual system, but one grounded in a whole way of life, usually associated with a school and a charismatic teacher. The apostles had appointed episkopoi, and they seem (from the NT) to be "successors" to the apostles. It's not that bishops were equals to the apostles, or had apostolic powers, but they were tasked, among other things, with guardianship with the deposit of teaching the apostles had received from Christ and promulgated throughout the world. A further suspicion I have is that his guardianship and maintenance/presidency of eucharistic rite had conceptual overlaps with the priesthood. However, whether this point was true or not doesn't matter for the longer reconstructive argument.
Anyway, a growing conflict emerged between bishops and "teachers", or those who took up roles more similar to philosophy. However, the conflict was, and would be, rather diverse in the form it took. Not every teacher saw their role as in opposition to the "church" and its bishops. Clement of Alexandria was a great synthesizer. He was the teacher at what would become the School of Alexandria, which was, in a way, a Christian philosophical school that had walked the line. Clement does not seem hostile to the episcopacy and the heap of Christians in the Church, but I think he seems to degrade them as lesser lights. He did not move his school out of the Church, but still saw it as the ground for serious Christians who wanted to ascend from merely being illuminated to being the "knowers", or the Gnostics. Justin Martyr, whose persecution and death further added sanctity to his name, was someone who also straddled the line, operating as a teacher somewhat in conjunction with the churches of Rome.
Of course, these are not figures we'd consider gnostics, for that label has generally been applied to those who've gone the extra step and either completely rejected the churches as degenerate and/or compromised, or at least unhinged the life of the gnostics from those lesser tiers of Christians. Unlike Clement, who looked down but did not abandon these soulish Christians, teachers like Valentinus and Ptolemey rejected associated with the church as simply too worldly, too craven, and all-around unenlightened. A major feature of their schools (which, as those who've broken off, and gone their own way, make them "heretics", or adherents of a hairesis, a separate way) was to emphasize revelations that either clarify or surpass the revelation recorded in the written, or orally reproduced, New Testament literature.
Emphasis should be placed on the first issue because it was the most slippery and would breed generations of heresy hunters. It was this teacher-centric movement that swirled around Origen's fame and infamy. Someone like Clement who straddled both sides of the fence, jealous bishops would hound Origen in his own day, who found refuge among other hierarchs who refused to turn him aside. Egyptian bishops, initially, rejected Origen's cavalier school, which was both probably an overblown judgement derived from wounded pride and fear of losing power, as well as a well-founded suspicion that Origen's teaching hid something for his elite students, and away from the masses of more simple Christians. While Arius represented a final gasp of this movement, eclipsed by an increasingly imperially integrated episcopacy, and being reborn within some parts of the monastic movement (which was not so worldly and educated as the philosopher-teachers), the Origenist crisis would carry on for centuries, usually hashed out and repopulated through monastic interlocutors and polemicists.
Taking this narrative, as I've drawn it, into account, one gets a better picture of the gnostic movement. It wasn't found so much in its extremes, but in how the extremes operated, thought, and made their case that has broader applicability among groups who would ultimately remain within, or at least connected to, the churches and their episcopal guardians. Not every gnostic was a Marcionite or a Valentinian. But their wild ideas were birthed within a context that was wider and more potent than many suspect. If we wish to understand the beating heart of the gnostic movement, we have to appreciate and evaluate its methodological point, not only or merely its cosmology. And yet, even so, we must not simply cast off their cosmological arguments either as simply silly fairy tales, for it's through these that their major concerns manifest.
Irenaeus is, I think, someone who grasped these dynamics quite well and responded with wisdom and zeal in his Against the Heretics. Of course, there are those modern liberals who, through a revisionist lens, anachronistically paint a zealous and powerful churchman (Irenaeus) attacking the free-thinkers of his day, wildly distorting and misunderstanding their doctrine, and foreshadowing future inquisitions. This generally ignores the fact that the philosophers usually attracted the wealthy and well-connected with promises of esoteric, secret, knowledge and mystical, if not magical, powers that may not only aid them in this life, but grant them glory or immortality in other realms, post-mortem, as well. In general, it was the churches that were the weak ones. But I digress.
After pages and pages of reconstructing varieties within the gnostic system, with their differing accounts of the two tetrads (four-fold entities) that make up the ogdoad (eightfold entity), producing the cosmic variety of the spirit world, Irenaeus ridicules the gnostic system. He does so by giving his own cosmology:
There is a certain Proarche [before-all-power], royal, surpassing all thought, a power existing before every other substance, and extended into space in every direction. But along with it there exists a power which I term a Gourd; and along with this Gourd there exists a power which again I term Utter-Emptiness. This Gourd and Emptiness, since they are one, produced (and yet did not simply produce, so as to be apart from themselves) a fruit, everywhere visible, eatable, and delicious, which fruit-language calls a Cucumber. Along with this Cucumber exists a power of the same essence, which again I call a Melon. These powers, the Gourd, Utter-Emptiness, the Cucumber, and the Melon, brought forth the remaining multitude of the delirious melons of Valentinus.A nasty, but delicious, satire of his gnostic opponents. But what's his point? Is Irenaeus just trying to laugh the disciples of Valentinus and Ptolemey out of the room with their ridiculous beliefs? Not exactly. Irenaeus continues:
For if it is fitting that that language which is used respecting the universe be transformed to the primary Tetrad, and if any one may assign names at his pleasure, who shall prevent us from adopting these names, as being much more credible, as well as in general use, and understood by all?Irenaeus' point is much more substantial than ridicule of beliefs that all modern peoples would find utterly bizarre. For what is the point of these gnostic myths? Valentinus and others like him believed they had received, discerned, or deciphered a credible way to describe the Real, of which the majority of Christians were too stupid or unenlightened to understand. But Irenaeus' casual recounting of the several myths in his matter-of-fact way is itself a kind of polemic? Why? Because these myths were told, self-consciously, as myths. These names and stories were a kind of mystically transformative language games that one entered into so as to find the truth at the end of the maze. Cloaked in mystery, solemnity, and authority, these stories pushed the adherents to dive deeper and deeper into the puzzle. As they swirled from name to name, from conjunctive union to conjunctive union, one's spirit ascended, unburdened by materiality and opened to a clarity of vision through the spirit-mind's eye (the nous). However, shine a light on these stories, drag them out of their dank and dark mystique into the day of common speech. What's the result? It sounds like utter rubbish. Irenaeus knows what he's doing. It's the same way a show like South Park mocked Scientology: tell the story simply as it is without the social apparatus and the shrouded mystery. Viewers laughed as they were confronted with a story about being possessed by dead alien spirits that were killed via volcano by an evil space overlord.
And yet Irenaeus' point goes further. For he is not to simply satirize these views, with an alternative as the common-sense of his day or promoting the cold, sterile, light of rationalism. He was a Christian after all; he proclaimed something that was equally absurd before a majority of his pagan contemporaries. Rather, Irenaeus' ridicule is grounded in the question of authority. Who gave Valentinus, or any of these charismatic-teachers, the right to name these names? As he would mock Colarbasus, a disciple of Valentinus, he describes the aeons being brought into existence as if he had been present at their birth! Again, it's not the ridiculousness of the story (as it was in the hands of South Park creators Stone and Parker), but the authority that makes the claims stand up to scrutiny. Why does Valentinus have special access to these ideas? Is Colarbasus really saying he was present at the birth of the aeons?
Epistemically, Irenaeus grounds his Christian convictions in what he received from the apostles. I'll return to this point at another time, when I discuss Irenaeus' views of scripture and tradition. However, simply put, Irenaeus points to a publicly accessible doctrine, given among and through the common life of the church, as that which was from the apostles. The NT must be read in the context it was produced, not subjected to tortured hermeneutical gymnastics that gets John 1 to be, actually, a retelling of how the Ogdoad came about. The testimony, as its received, recounted, taught, and passed along, determine the language we can, and can't, use. To speak about divine things, we are not, we can not, be left to our own devices. Otherwise, our accounts are just as silly as the generation of Cucumber and Melon from Gourd and Emptiness (presumably a reference to a hole in the ground). And why not? This story makes far more sense to the generally agrarian people of the empire. Why can't Dr. Seuss be a prophet for the enlightened? The urbane would balk, but Irenaeus takes the side of the common and uneducated: what's the difference? more people could grasp esoterica in terms of fruit than abstracts.
Irenaeus point has far more range than simply a means to rebut gnostics, both ancient and modern. One can, for example, take issue with how many Calvinists will try to explain election or their doctrine of covenants. They'll say things like "in eternity past" and tell some story about the 'pactum salutis' or in some pre-temporal moment where God plucked out the elect He was to save. The problem, as Irenaeus helps us see, is that none of this is given in scripture. None of this language is given. So when you hear some Evangelical tell some quasi-tritheistic story about how the Godhead sat down and decided (or the Son volunteered) to save humanity, we ought to blush with embarrassment. Where you there? How do you know what one of the Godhead said to the other? It's a systematic theology working back to generate, and spread, a narrative account to explain its meaning. For Irenaeus, someone who was very much self-aware of his apostolic lineage, the historical was the authentic, for it was only in the teaching delivered from the Christ to His apostles, and guardedly passed down through the episcopal guardians. This witness testimony is precisely not myth, for it's not something to be excavated by a foreign template that, through immersion, one is brought to truth. It's not a dialectical soul searching, batted between a desire for the truth and mythical writings until the mind is unlocked. Rather, it's hearing and believing.
This should also make us wary of any claim to philosophical necessity. Intellectual cleverness, and claims that one idea leads to another, may easily bamboozle, and soon we're describing realities that are simply not given to us. Far beyond predestination and covenants, this same wariness can be applied to many Christological controversies as well. We must never leave the question of authority, for it's this that grounds our language and, ultimately, our access to any claim on the truth. Without it, we are trapped in the world of men and earthly things, and death is all that awaits us. Hence fantasy is always the preferred option, but it is, truly, a sickness unto death.