we are all Gnostics now

Been readin' Tertullian, thanks to my brother, who started the whole thing by mentioning that some of his students are closet Gnostics--and they don't even know it. (Read up on Gnosticism here, if you're so inclined.)

My brother's recapitulation of Tertullian's arguments against Marcion is coherent and fair.

...the "spiritual body" seems akin to the "spiritual man" of 1 Corinthians 2, the "man who lives through the Spirit." Given all of Romans 8 and Paul's use of "spiritual" in 1 Corinthians (as well as his statements about the body being a "temple" of the Spirit, the most natural meaning of "spiritual body" in 1 Corinthians 15 is "a body that is under control of the Spirit."

(Compare this with Tertullian, Chapter LIII.)

Christians ought to believe in the resurrection of the body. But does failing to believe in the "literal" bodily resurrection--or to understand the subtleties, semantics, and implications of Tertullian's position--make them Gnostics?

The argument fails on lack of evidence and oversimplification.

First, the primary evidence is hastily generalized (from a group of sixteen students who either misunderstood the resurrection of the body, or held no positive belief on the subject, hardly making them "Gnostics"), and insufficiently warranted. That the evangelical church ignores spiritual disciplines may be true, but that the cause is Gnosticism is assumed rather than proven. The same is true of the supposed forgetting of the "corporeality" (body-focus) of worship. Closing eyes to pray, kneeling, standing to sing, raising arms, clapping, singing itself, or taking communion... these are all bodily activities, as corporeal as they come, barring calisthenics.

Hence, I asked for a survey of Christian belief--is there any sort of correlation between wishy-washy belief in a bodily resurrection and lax spiritual discipline, or "corporeality" in worship? That would solve the question, in my mind, whether these borderline heresies actually make a difference in religious practice. As I noted before, using the practice as proof of belief may not always work; my brother even admits that Gnostics and Christians might both fast, for example, for entirely different reasons and with different attitudes. He makes the argument, though, that a Gnostic Church is different from a normal Church in three main respects; this brings up the second problem of oversimplification.

1) Worship: The historical Christian church has always incorporated movement in their corporate worship services. Also, "sensory input" (I'm not sure what the word would be) has played prominent roles in numerous traditions (see incense, icons, rosaries, etc.). A Christian that does not think the body important will neglect the richness of these aids.

Gnostics, as noted below, see the body as "important," but essentially un-good (if not outright "evil"). How Gnostic worship looked (or would look today) I have no idea. But I can't imagine it would involve floating in sensory-deprivation tanks. I could be wrong.

2) Disciplines: The historical Christian church has also advocated "spiritual disciplines" as means of developing one's relationship with God. Ironically, these "spiritual disciplines" are often very physical (see fasting, solitude, silence). Personally, I experienced a much richer prayer life once I began praying on my knees and have also experienced significant spiritual growth while fasting. If the body is not viewed as an intrinsic part of our salvation, then it is difficult to see why these disciplines would "work." Yet I have the testimony of 2000 years of Christian tradition (and personal experience) informing me that they do.

Gnostics have their own spiritual disciplines; this point is moot, as noted above.

3) Sexual ethics: See 1 Corinthians. This was the whole problem. They didn't consider the general resurrection to be physical and subsequently thought they had license to act (sexually) however they wished. This was also Jonathan's point in the comments to my first post.

Gnostics have differing opinions on the matter of sex. Also, the sexual problems in Corinth may have had nothing to do with the attitude toward the resurrection; Corinth was a crossroads of all sorts of religious and philosophical systems. As Daniel B. Wallace writes,

The problem of the identification of the opponents is that they were no doubt a mixed bag, an amorphous entity of several factions. This can be seen by the very nature of Corinth itself, a rather cosmopolitan city which was constantly having an influx of new ideas. The church at Corinth is analogous to any church in southern California in the 1960s/1970s: the “land of fruits and nuts” involved such a diverse influx of ideas, fads, and avant garde heresies that to pin down any unified group as the opponent of the church would be like trying to nail Jell-O to the wall!10 In other words, Paul’s opponents at Corinth were Jews, proto-Gnostics, libertines, ascetics, ecstatics, realized eschatologists,11 anti-resurrectionists, and more! It may be an overstatement to call all of these “opponents,” but it is obvious that several factions existed in Corinth (cf. 1:10-17) and the problems needed to be dealt with seriatim.12

In short, Matt mischaracterizes Gnosticism, conflating contradictory (and competing) strands. Again, from Wikipedia:

Some Gnostic sects were Christians who embraced mystical theories of the true nature of Jesus and/or the Christ which were out of step with the teachings of orthodox Christian faith. For example, Gnostics generally taught docetism, the belief that Jesus did not have a physical body, but rather his apparent physical body was an illusion, and hence his crucifixion was not bodily.

Most Gnostics practiced celibacy and asceticism, on the grounds that the pleasures of the flesh were evil; a few however practiced libertinism, arguing that since the body was evil they should defile it. This led to further distrust, and was an accusation leveled against other groups who did not follow this practice.

Without accurate data, we're left with the "affirming the consequent" fallacy. We have:

Gnostics deny the corporeality of worship, and are lax in spiritual discipline. (Note that this premise itself is questionable.)

The church shows signs of both.

Therefore, the church is falling prey to the influence of Gnosticism.

Matt should ask his students whether they believe Jesus did not have an actual physical body; this would be a clearer way to judge if they're really nascent Gnostics, or--more likely--just theologically ill-informed. I would argue that the latter is far more relevant to the discussion of the watering-down of Christian rituals or disiciplines. If I'm to hastily generalize from my own former religious experience, the problem isn't heresy; it's anti-intellectualism and, relatedly, utter disregard of early Christian history.