Gnosticism is behind all the New Age false programs and so-called spiritualities. But, here is the real definition from the Catholic Encyclopedia.
Whereas Judaism and Christianity, and almost all pagan systems, hold that the soul attains its proper end by obedienceof mind and will to the Supreme Power, i.e. by faith and works, it is markedly peculiar to Gnosticism that it places the salvation of the soul merely in the possession of a quasi-intuitive knowledge of the mysteries of the universe and of magic formulae indicative of that knowledge. Gnostics were "people who knew", and their knowledge at once constituted them a superior class of beings, whose present and future status was essentially different from that of those who, for whatever reason, did not know. A more complete and historical definition of Gnosticism would be:
A collective name for a large number of greatly-varying and pantheistic-idealistic sects, which flourished from some timebefore the Christian Era down to the fifth century, and which, while borrowing the phraseology and some of the tenets of the chief religions of the day, and especially of Christianity, held matter to be a deterioration of spirit, and the wholeuniverse a depravation of the Deity, and taught the ultimate end of all being to be the overcoming of the grossness ofmatter and the return to the Parent-Spirit, which return they held to be inaugurated and facilitated by the appearance of some God-sent Saviour.
However unsatisfactory this definition may be, the obscurity, multiplicity, and wild confusion of Gnostic systems will hardly allow of another.
Gnosticism reveals itself among the charismatics and those who are looking for special knowledge. It accounts for self-satisfied groups who only want good feelings and the cookies of consolations from God.
But the real dangers, are the beliefs in those deities or powers or even spiritualities not connected with Christ Himself or the Trinity. There is no such thing as neutral powers.
Here is the CE again.
Gnosticism is thinly disguised Pantheism. In the beginning was the Depth; the Fulness of Being; the Not-Being God; the First Father, the Monad, the Man; the First Source, the unknown God (Bythos pleroma, ouk on theos, propator, monas, anthropos, proarche, hagnostos theos), or by whatever other name it might be called. This undefined infinite Something, though it might be addressed by the title of the Good God, was not a personal Being, but, like Tad of Brahma of the Hindus, the "Great Unknown" of modern thought. The Unknown God, however, was in the beginning pure spirituality; matter as yet was not.
This source of all being causes to emanate (proballei) from itself a number of pure spirit forces. In the different systems theseemanations are differently named, classified, and described, but the emanation theory itself is common too all forms of Gnosticism. In the Basilidian Gnosis they are called sonships (uiotetes), in Valentinianism they form antithetic pairs or "syzygies" (syzygoi); Depth and Silence produce Mind and Truth; these produce Reason and Life, these again Man and State (ekklesia). According to Marcus, they are numbers and sounds.
These are the primary roots of the Æons. With bewildering fertility hierarchies of Æons are thus produced, sometimes to the number of thirty. These Æons belong to the purely ideal, noumenal, intelligible, or supersensible world; they are immaterial, they are hypostatic ideas. Together with the source from which they emanate they form the pleroma.
The transition from the immaterial to the material, from the noumenal to the sensible, is brought about by a flaw, or a passion, or asin, in one of the Æons. According to Basilides, it is a flaw in the last sonship; according to others it is the passion of the femaleÆon Sophia; according to others the sin of the Great Archon, or Æon-Creator, of the Universe.
The ultimate end of all Gnosis is metanoia, or repentance, the undoing of the sin of material existence and the return to the Pleroma.
In the greater number of Gnostic systems an important role is played by the Æon Wisdom — Sophia or Achamoth. In some sense she seems to represent the supreme female principle, as for instance in the Ptolemaic system, in which the mother of the seven heavens is called Achamoth, in the Valentinian system, in which he ano Sophia, the Wisdom above, is distinguished from he kato Sophia, or Achamoth, the former being the female principle of the noumenal world, and in the Archotian system, where we find a "Lightsome Mother" (he meter he photeine), and in which beyond the heavens of the Archons is he meter ton panton and likewise in the Barbelognosis, where the female Barbelos is but the counterpart of the Unknown Father, which also occurs amongst the Ophites described by Irenaeus (Against Heresies III.7.4).
I am sure many of you will recognize just some of these beliefs as held by your family members or even pastors.
There is more, but the dangers include also, a clinging together of little groups of people who think that they are in the know about things in the Church and no one else. These cliques may be in chancery offices, or schools, or parishes and purposefully exclude others who are not in the know.
The other great error of Gnosticism is the denial of the need for personal redemption or salvation-a person just grows as society evolves, and another heresy, that of progressivism, which holds that people will evolve into holy, good people, is connected . This is the great heresy of Star Trek. Gnosticism denies grace and redemption and relies on the secret knowledge of the few.
Part of the nonsense and nastiness on line has been caused by cliques who either are in the know or want to be in the know or think they are in the know.
Thankfully, I aspire to none of this private, inner knowledge of the workings of the Church. I am merely, a Catholic.