So, I'm listening to a lecture on Early Christianity (by Prof. Luke Timothy Johnson of Emory University), and he goes into four possible inadequate definitions of what a religion is.
A descriptive definition of religion can be approached from four definitions: Membership in a group, ritual behavior, belief or doctrine, and/or morality. I thought it would be interesting to approach Modern Gnosticism from these angles.
membership in a group:
This sort of definition is unimportant to Gnosticism. You don't have to be an ethnic group, have been born into it, convert, or even say you are a gnostic. Gnostics tend to be self identifying, and they move into and out of the definition as they please.
Gnostics do tend to have a negative identification: I'm not a Christian, I'm not a Jew, etc. It's not universal, but I have found it fairly common.
Some Gnostics have highly ritualized behavior coming out of the traditional and esoteric sacraments and rituals, some develop new ritual behavior, or pull in a syncretic manner from older traditions. Some invent wholly new behaviors, and some ignore ritual altogether. I'd give this category a middling importance.
Belief or Doctrine
There are a few core doctrines that are very important, there are others that can be accepted or not. The belief in the relevance of personal experience is widespread. Belief in the idea of liberation is also quite prevalent. Other beliefs and doctrines vary based on the flavor of Gnosticism.
This has almost no bearing in Gnosticism. The morals range from ascetic self denial to libertine philosophies. The so called 'left hand' and 'right hand' paths. Morality is an individual concern, not a concern of the religion. Contrast Evangelical Christianity, with it's extreme emphasis on moral behaviors. (Whether those behaviors are enacted or not is not the point, they are emphasized).
So, from the descriptive definitions we have here, we have Modern Gnosticism as a set of core doctrines, to which can be added ritual behavior. Morality and group identification are individual concerns. This definition is necessarily vague, but try to do a similar definition for Christianity, and you'll see the weaknesses of this approach for a whole tradition.
Now, if we were to take, for example, American Roman Catholic as a category, we'd end up with Strong group identification, Strong ritual behavior, middling doctrine (there's a lot of doctrines in RC that are ignored in America), and a fairly strong moral emphasis.
Evangelical Christianity, by contrast, has strong group identification (have you been saved?), but weak ritual behavior, weak doctrine, and a strong moral emphasis. I say weak doctrine because two evangelicals may disagree on several differing interpretations of the bible, and biblical interpretation is an individual concern.
Ecclesiastical Gnosticism could come down with stronger group identification (as there's a group to identify with), definite ritual behavior, a stronger but still very vague doctrine, and again almost no moral emphasis, although there is a bit.