One thing that's always interested me about art is it's process of changing the functions of ordinary objects. In this instance a chair nailed to the ceiling becomes a usless chair as no one can sit on the ceiling unless they're strapped to the chair.
Now the chair takes on a different meaning. The perception of the object has to change due to the surrendering of it's function. Can you now call it a chair if it no longer functions like one? So what is it? Also now that you have photographed it, it's gone through another process removing it another step away from a chair.
Joseph Kosuth One and Three Chairs may help to explain what I am talking about here. This is a concept art piece that involves three chairs. In the middle sits a chair on the left is a photograph of a chair and on the right is a dictionary definition of a chair. You could say that all three are chairs but one only actually functions as a chair. You have a visual representation of a chair (Photo) and a written code of a chair (Dictionary definition)
I'd argue that what is most interesting about your photograph is the manipulation of perception. First you ruin it's function as a chair by nailing it to the ceiling making it into a hanging ceiling object. Then taking a photo of it removing it one step away from the object hanging from the ceiling and making it a visual representation. Now if you turned the photo upside down it becomes a visual representation of a functioning chair again.
I know you have other ideas about your photo but I just wanted to share this little thought about perception using your work as a basis. I hope you understand and found it interesting as it interests me.
This is all very valid! Thank you very much for your thoughts. Awesome contribution!