Gnosticism is defined as believing that one is saved by having a certain knowledge. Believe it or not, this has become the rule of thumb of the modern gospel. Here is what the whole gospel of gnosticism is founded on:
Implying that knowing Jesus as Lord, or that he died for us, is salvific.
I know you probably mean well, but that's a long ways from the real meaning of Gnosticism. It really requires an understanding of the very basis of pagan philosophy to define it.
The way the early Gnostics (and later Gnosticism) apply the word is not as 'theoretical knowledge', but in the 'direct experience knowledge' sense involving mystical enlightenment.
A more apt definition is, Gnosticism is the false practice of seeking to 'know God through direct mystic experience' vs. believing in God through divine revelation by The Holy Spirit in His Word.
Gnosticism began in the 2nd century A.D. with a group that joined Greek Neo-Platonist philosophy with Christian Doctrine. One of their worst falsehoods was the idea that our Lord Jesus Christ did not die on the cross, but that His disciples removed Him beforehand, and He lived to old age, married, and literally had flesh children.
Modern Gnosticim is what the modern
Holy Blood, Holy Grail type stories are about, including movies like
The Da Vinci Code. One of the last falsehoods pushed in
The Da Vinci Code was the erroneous idea that Christ's powers of the mystic were directly transferable to a supposed flesh lineage He had.
What Gnosticism really is, is esoteric occultism. That's where 'mysticism' is derived. This is why some of the early Church fathers in the 1st - 4th centuries wrote so much against the falsehoods of the Gnostics.
Ultimately, it's about the vain attempt of some men to become 'a God'. That's the main goal of esoteric mysticism, and was the goal of the ancient pagan 'Mystery Religions'.
Later European followers of such spiritual esoteric style Christian movements were those like Jacob Boheme, Emmanuel Swedenborg, etc. It contributed much to the later 19th century 'spiritualist' movements in the U.S.A. and Charismatic ideology. Some later Catholic monks got trapped in it, and there still exists forms of it among those groups, but also among the Protestant Church also.
But those Gnostic type movements have NOTHING to do with Divine Revelation by The Holy Spirit or through God's Word. The difference is with the idea of a 'practice', or 'method'. Gnosticism or Mysticism seeks the use of an esoteric 'method' of exercises in order to more closely approach God in order to have 'direct' mystical-like experiences of the hidden mysteries of God. In THAT sense is how their 'gnosis' is meant, i.e., to know by direct experience by mystic practice.
