Conscience is at least partly a product of reasoning, inasmuch as it requires recognition of the salient interactive phenomena and anticipation of their consequences; but it seems plain enough that conscience is brought into play at levels determined by the specific and unique combination of internal and external environments of the individual. Culture is, of course, a significant factor in the nature of the environment.

Given that reason is a prerequisite for conscience, I would say that any life form capable of sufficient reasoning power has potential for conscience. It may be said that our comparatively remarkable ability to reason defines us as human, but while that's probably be true on Earth, ET might (reasonably) argue the point.

"Time is what prevents everything from happening at once" - John Wheeler