As I understand it, the orthodox communist belief in proletarian revolution comes from three major claims:
1) The proletariat has the capacity to revolutionise society, due mainly to its central place in economic production, and to its concentration in cities and large businesses (in contrast to the isolation of peasants or small artisans);
2) The proletariat has the motivation to revolutionise society, because capitalism necessarily frustrates its interests and locks it in a class struggle that it is constantly losing;
3) If and when the proletariat revolutionises society, the result will be socialism – a society without systematic class oppression, because insofar as someone’s economic role is proletarian, it doesn’t imply a subordinate person of another class (in the way that a lord’s role implies serfs, etc).
It’s a nice collection of theses, but clearly something is missing, or needs to be said more fully, because the supposed conclusion hasn’t been reached yet. Of course, perhaps we shouldn’t expect it to have been so soon, but it’s still striking that our closeness to it seems by many standards to have substantially declined.
What interests me is the possibility that one of these three points may be in conflict with another – in particular, that the motive mentioned in point 2. may conflict with the end postulated in point 3.