“Gnosticism” actually is capable of a specific enough meaning to be useful, and was useful in the first few centuries of the church. As the Greek term gnosis implies, it describes any soteriology keyed on knowledge in general, but often this knowledge takes the form of a cognitive secret.
Before you knew this thing x, you were in darkness, now that you have received the secret, you are “saved”.
Almost every religion and quasi-religion other than NT Christianity is gnostic; they all start with the common assumption that we need to know something else. It is a variation of the snake’s seduction of Eve in the garden; “you just need to know one more thing, then you will see through the illusion”. Many strains of Christianity have fallen victim to this perennial deviltry.
Paul, in stark contrast with all that was around him, argued vehemently and often that salvation is NOT by gnosis, but by fide — trust in a Person, and not a thimbleful more knowledge or even cognitive awareness to help you get to that moment of radical submission. It was salvation by faith that was the revolutionary assertion, and Paul was the revolutionary.
Of course, AFTER faith does come cognitive change (cf the Latin formula fide quaerens credum and pardon my dashed off Latin), EVEN mystical experience, which is never sought and never promised to catechumens but is often given by grace. So the gospel always says believe in the good news, THEN add to your faith knowledge and virtues, and the gnosticism which is the world’s multifaceted religion says “learn one more thing” or “do this one thing and you will be illumined”.
It is actually a form of rebellion against the gospel. The soul cries out it has not heard enough to yet believe, the soul cries out it knows that it needs one more thing even though the gospel may say “you have heard the good news, now decide.”
Because, after all, you can be illumined and stay right where you are. You can grasp a secret long dark to you and still be in the same static place you were when you were ignorant. But only Jesus demands that you, by trusting, existentially MOVE, and follow Him. And you can be as ignorant as you were yesterday and in faith be walking behind Him and be saved.
Every religious system that looks for or hopes for an enlightenment is gnostic. The gospel is unremittingly hostile to all other religious forms, because they do not sufficiently strip the soul of all that keeps it on the wrong side of the eye of the needle, the gate of the kingdom, the moment of trust.
We’ve become more sophisticated in our gnosticism; we would laugh at anyone who asked us to go down into a pit at midnight and have bull’s blood poured over us as we say the secret incantation. But we will stop in Wal-Mart and pick up a book that says “The 5 keys to happiness”.
Same thing: gnosticism.
I didn’t mean to rant at you, but I think much is missed in modern disussions of the word “gnosis”, and what is missed is just how radical a moment it was when Paul of Tarsus said “we assert that a man is justified by faith.”