> 2) proving the inevitable demise of capitalism,
> which if not a doomed project isn't exactly looking like a blessed
> one.
Probably the motives are more varied, but I rather fear that this motive in rather worse form prevails in some (many?) cases: The desire to prove that Marxism is true. My reason for fearing this motive is that it is at least a move in the direction of making Marxism a religion -- by which I mean any theory that makes belief in the theory itself a virtue (salvation by faith alone as it was expressed in the Reformation).
I would agree that a desire to prove the inevitability of capitalism's collapse can also, though not necessarily, be a religious motive. It depends upon the extent to which such a desire is embodied in scholasticism -- that is separated from any sort of practice whatever. Another route to religion is to take theory which is explanatory at a high level of abstraction and turn it into a formula for practice -- which I like to image in terms of demanding that quantum mechanics teach us directly how to cook our breakfast.
There is sort of a highly generalized reason, incidentally, to believe (or even take for granted) the *eventual* demise of capitalism. History is very long and varied and gives liittle reason to believe that *any* set of social relations is eternal. That, however, may not be a particularly consoling position.
Carrol