Ren, Social Properties, and Western Comparisons
Of course, for Aristotle, it appears that sometimes the individual's possession of a virtue had to do with external chance--one can only be generous if one is successful at giving, rather than simply having the intention to give, for example. But even Aristotle's virtues must be considered things had by an individual.
I believe that the notion of ren for Confucius is very different than this. We get into problems, I think, reading Confucius as an Aristotle-type "virtue-ethicist" for this reason (among others I won't get into here). Ren cannot be thought of as a virtue in the Aristotelian sense mainly because ren cannot be possessed by one in the way a virtue can.
Confucius talks of one's thoughts being on ren, or guarding ren. Why should we take this as meaning that one guards ren in oneself? Given the social meaning of ren, it seems more plausible to me to hold that Confucius thought that ren could be guarded simply because ren is a property of a social group, perhaps like peace or harmony (which, I know, could also be applied to individuals, but would of necessity reference different parts of individuals, --i.e. the legs are in harmony with the arms, etc.).
Ren as a property of groups can be initiated by an individuals, just as can peace within a group. So the notion of ren as a social property does not make it impossible to make sense of talk of individual involvement with ren. Most ethical properties, in fact, seem to have an individual as well as social component. However, we tend to put the emphasis on one or the other in coming to give an account of the concept--so that honesty, for example, is focused on the individual, even though there is certainly a social aspect of honesty.
I think my opposition to letting ren be cast as a virtue in the Aristotelian sense has much to do with the neglect of the ineliminably social aspects of ren that follows (which is surely the key to the concept), as well as with strong reservations about understanding ancient Chinese thinkers through the goggles of western philosophy.