In Shirley Jackson's novel "The Haunting of Hill House" what is actually haunting the house?
Obviously there are not any specific ghosts seen but the possibilities of spirits from past inhabitants of the house don't seem rational either. Certain stories are mentioned eluding to possible sources of this supernatural but there is not one to be pin-pointed. I know there is not a specific answer but any reasonable suggestions would be greatly appreciated.
The short answer is, you're right. We don't know for sure. In fact, that's one of the things that makes the novel work so well. So long as we don't know exactly what is going on, suspense builds, and anything is possible. We don't know what the rules of this world are, and so we don't know what to fear or trust. Once we find out it is X (whatever X is), we can relax somewhat.
That said, I think Jackson manages to suggest it is the spirit of the house itself. You know how the ancient Greeks thought of individual streams as having spirits living in them? I think this is the spirit of the house itself. It is constructed, rather than natural, but I think Jackson's given us an innately unnatural place.
I think the answer is right there in plain sight. Note the passages in the first and last paragraphs to "Hill House, NOT SANE" (emphasis mine). Also, Dr. Monague expounds to the others on "evil houses".
what are some themes of Haunting of Hill House