Demiurge

Gnosticism attributed falsehood or evil to the concept of Demiurge or creator, though in some Gnostic traditions the creator is from a fallen, ignorant, or lesser—rather than evil—perspective, such as that of Valentinius.
Plotinus

The Neoplatonic philosopher Plotinus addressed within his works Gnosticism's conception of the Demiurge, which he saw as un-Hellenic and blasphemous to the Demiurge or creator of Plato. Plotinus is noted as the founder of Neoplatonism (along with his teacher Ammonius Saccas).[40] In the ninth tractate of the second of his Enneads, Plotinus criticizes his opponents for their appropriation of ideas from Plato:

From Plato come their punishments, their rivers of the underworld and the changing from body to body; as for the plurality they assert in the Intellectual Realm—the Authentic Existent, the Intellectual-Principle, the Second Creator and the Soul—all this is taken over from the Timaeus.
—Ennead 2.9.vi; emphasis added from A.H. Armstrong's introduction to Ennead 2.9

Of note here is the remark concerning the second hypostasis or Creator and third hypostasis or World Soul. Plotinus criticizes his opponents for “all the novelties through which they seek to establish a philosophy of their own” which, he declares, “have been picked up outside of the truth”;[41] they attempt to conceal rather than admit their indebtedness to ancient philosophy, which they have corrupted by their extraneous and misguided embellishments. Thus their understanding of the Demiurge is similarly flawed in comparison to Plato’s original intentions.

Whereas Plato's Demiurge is good wishing good on his creation, Gnosticism contends that the Demiurge is not only the originator of evil but is evil as well. Hence the title of Plotinus' refutation: "Against Those That Affirm the Creator of the Kosmos and the Kosmos Itself to be Evil" (generally quoted as "Against the Gnostics"). Plotinus argues of the disconnect or great barrier that is created between the nous or mind's noumenon (see Heraclitus) and the material world (phenomenon) by believing the material world is evil.

The majority of scholars tend[42] to understand Plotinus' opponents as being a Gnostic sect—certainly (specifically Sethian), several such groups were present in Alexandria and elsewhere about the Mediterranean during Plotinus' lifetime. Plotinus specifically points to the Gnostic doctrine of Sophia and her emission of the Demiurge.

Though the former understanding certainly enjoys the greatest popularity, the identification of Plotinus’ opponents as Gnostic is not without some contention. Christos Evangeliou has contended[43] that Plotinus’ opponents might be better described as simply “Christian Gnostics”, arguing that several of Plotinus’ criticisms are as applicable to orthodox Christian doctrine as well. Also, considering the evidence from the time, Evangeliou thought the definition of the term “Gnostics” was unclear. Of note here is that while Plotinus' student Porphyry names Christianity specifically in Porphyry's own works, and Plotinus is to have been a known associate of the Christian Origen, none of Plotinus' works mention Christ or Christianity—whereas Plotinus specifically addresses his target in the Enneads as the Gnostics.

A.H. Armstrong identified the so-called "Gnostics" that Plotinus was attacking as Jewish and Pagan, in his introduction to the tract in his translation of the Enneads. Armstrong alluding to Gnosticism being a Hellenic philosophical heresy of sorts, which later engaged Christianity and Neoplatonism.[44][45]

John D. Turner, professor of religious studies at the University of Nebraska and famed translator and editor of the Nag Hammadi library, stated[46] that the text Plotinus and his students read was Sethian Gnosticism, which predates Christianity. It appears that Plotinus attempted to clarify how the philosophers of the academy had not arrived at the same conclusions (such as dystheism or misotheism for the creator God as an answer to the problem of evil) as the targets of his criticism.

Emil Cioran also wrote his "Le mauvais démiurge (The Evil Demiurge)", published in 1969, influenced by Gnosticism and Schopenhauerian interpretation of Platonic ontology, as well as that of Plotinus.