Lisa asked:
Which is most real: the chair you are sitting on, or the molecules that make up the chair?
Answer by Nathan Sinclair
Reality doesn’t come in degrees. Things are real or not, but no real object is any more or less real than any other. The commonplace example of a property without a degree is pregnancy — just as there is no-one can be half-pregnant, nothing can be half real.
Both the chair and the moecules are real, and thus as real as each other. Perhaps it seems odd that two different real things (the molecules and the chair) can be at the same place at the same time. But this is simply because the molecules are parts of the chair. It is no more odd than that some of my body is in the same place as my arm – my arm is a part of my body.
Answer by Helier Robinson
There are two definitions of reality. One, which might be called empirical reality, is all that we perceive around us that is not illusory. (The illusory is unreal by either definition.) The other, which might be called theoretical reality, is all that exists independently of being perceived: that is, it exists regardless of whether anyone perceives it or not. (‘Theoretical’ means ‘non-empirical’.)
The (empirical) chair that you are sitting on is mostly empirically real, the molecules that make it up are (very probably) theoretically real. Note that these molecules cannot be perceived; many people these days believe molecules to be empirical because structures of them can be imaged by a scanning tunnelling microscope. But the microscope only produces an image of the molecules, just as an electron microscope produces an image of a virus and an optical microscope produces an image of a bacterium. In each case the microscope does not enlarge the real object, it only enlarges an image of it. (And, by the way, some molecules are empirical: a diamond is a single molecule.)
Ask a Philosopher 
