Imagine, if you will, a person, but not any actual person. Let’s call the person you imagine Jerry. When you imagine Jerry, do you imagine Jerry having a middle ear? Do you imagine Jerry having eyelashes? (If you particuarly focussed on the eyelashes when imagining Jerry, think of some other visible but not particularly salient body part, like cuticles.)

I think the answer in each case is no, though the answer to a similar question is yes. If you think of your imagination as a little fiction, it is fictional that Jerry has a middle ear, and eyelashes, and cuticles, and so on. That’s because fictions, including very simple fictions like __Jerry exists__ are governed by what Walton calls the Reality Principle, which (roughly) says that real world facts are made fictional unless something stops them being imported into the fiction. But I don’t think you imagine Jerry having all these features.

I think imagining a person in full detail, right down to the cells and beyond, is beyond the capacity of any individual, although you can imagine a person and it be fictional that they have all kinds of detailed characteristics. So I think you can’t imagine a zombie, though (for all I’ve said here) you can imagine a zombie-like creature in rough outline and it be fictional in the imagination that the creature is a zombie. But this is very tentative, even for a blogpost.