.

As a philospher, I would say that if the glass was in the forest and no one was there to witness it, would it be half anything?

As a financier, I would say that the glass is invested in 50% liquid assets.

As a physicist, I would say that we don't really know because the act of sampling the glass alters its contents.

As a psychiatrist, I would ask, "What did your mother say about the glass?".