Because of the sheer variety of undead in fiction, it's impossible to give a satisfactory answer. And, in fact, by accepting the zombies can exist, you have to accept that zombies can exist - there isn't a further stretch of the imagination needed to accept they exist under some condition but the rest of their existence goes unchallenged by any doubt. It's the same stretch of the imagination. It's part of the initial premise. By being OK with the undead as a premise, you've already acknowledged they cannot be but are. By saying "but under these circumstances they are improbable" is bizarre as they are impossible under all.camazotz said:The number of people here who prefer to default to "fiction, ergo no effort required to engage imagination" is saddening. The OP made it clear he knew we were discussing the fiction, so why even bother to post if you're not going to engage the topic creatively?
So all this means that unless talking about specific undead, where perhaps some rules and explanation is established, there is little reason to "engage creatively". It's like trying to find an answer to "why are the suits yellow?" - there may be a variety of reasons depending on what exactly are we talking about but without any specifics...they just are.