How do we define a Christian?

I was thinking again recently about a question that arose at a Society of Christian Philosophers
meeting last Fall. One plenary speaker raised the
issue--I forget the context--of whether Jesus was a Christian by currently
common conceptions. The talk was fairly fragmented, but I was led to
reflect on a couple of things (one was whether robot's could become Christians,
perhaps I'll blog on that too) as a result and this was one of them. I'd
had some discussion on this once in High School, so it was fun to think about it
again.

Assume we want Jesus to satisfy the predicate "is a Christian" (I'm inclined
to think we should, but I can see reasons for denying this). What seems to
follow quickly is the No Cognitive Definition Thesis:

NCD No definition of what it is to be a Christian which appeals only
to cognitive states of the subject will be adequate.

Cognitivist definitions run quickly into the Demon Problem stated by James:
"You believe that God is one? Good. So do the demons!" Even if
you don't believe there are such things as literal demons a good definition of
"Christian" should be such as to rule out (evil) demons in the worlds in which
they exist. But it seems that any creed (construed propositionally) could
be endorsed by Lucifer himself (the caveat is intended to address both the
potentially extra-propositional commitment inherent in creeds and the use of
indexicals--like "was crucified also for us under Pontius Pilate").
How then to define "Christian?"

First, I should say that, inspired by a comment I vaguely recalled in
Swinburne's _Faith and Reason_, I tried to resist this conclusion by attempting
to find some way of representing putative non-propositional content
propositionally. I wasn't happy with the results.

It also seems problematic to define a Christian in terms of any kind of
success. For example if we defined thusly

SCD A Christian is one who follows Christ's teachings

then there aren't many Christians! One option is to go vague:

VCD A Christian is someone who generally follows Christ's teachings.

But I think this is fraught with problems. My favored approach is to
move to the level of intentions:

ICD A Christian is one who is committed to following Christ's
teachings.

I think this meets the desideratum of making Christ satisfy "Christian" and
places the emphasis on internal rather than external factors without completely
leaving out the external (such commitment is stipulated to entail a disposition
to act in the right way). This definition inherits general problems with
dispositional definitions, but I'm not really worried about that. This definition leaves out out Hebrew Patriarchs and Pious Pagans, but
we can introduce separate terms--"Anonymous Christian", "Honorary Christian"--to
handle these cases. One problem I see is the indeterminacy of "Christ's
teachings". As a Catholic, I'm not as worried about this part, since the Magisterium
will make that fairly determinate, though Protestants of some stripes will have
to worry about whether it includes, say, Mormons or Jehovah's Witnesses.

The bottom line is that I don't think the holding of any set of beliefs
entails that one is a Christian. Whether being a Christian entails that
one has any particular set of beliefs, and if so what they are, is a separate,
and difficult, matter. I don't think this thesis should be very
controversial, but I think the point is perhaps under emphasized among Christian
intellectuals. Furthermore, stating that having certain beliefs does not
constitute being a Christian is not to say what *is* sufficient. I've
attempted to do that with ICD.