'''Is the glass half empty or half full'''
'''Is the glass half empty or half full''' is a common expression, used rhetorically, indicating that a particular situation could be a cause for optimism (half full) or pessimism (half empty). It depends on how you look at it. The physicists will say that it is completely full - half water, and half air. A mathematician will take into account the meniscus, and a chemist would take into account..