[Jason Abbadon]

Well, at a sub-atomic level, it's very little except electromagnitism- mostly empty space with electons spinning around a proton, with huge (comparitive) distances between them.
The only reason we percieve the char as solid is because our own EM fields push against it's (combined) field and photons bounce off it, so we cant see through it...

But yeah, on a functional basis, a chair is a chair....unless it's some trickery of liht as can be done with mirrors or projectors- they you have a bunch of students writing about a projected image and thinking what a stupid assignment it is- as it's obviously there...

Stage magicians make objects on a stage appear and vanish all the time- and the audience has no clear idea as to what's real and what is deception or mis-perception.

At a distance, is the chair any more certainly "there" without touching it than images in a IMAX 3D movie? If you never saw 3D before, it'd be pretty shocking.

Thus, it's somewhat subjective- perception altering belief based on stimuli.