Is the glass half empty or half full?

common expression regarding optimism or pessimism

Is the glass half empty or half full? is an idiom.

A glass of water either half empty or half full.

The question is a common expression with both an obvious meaning and a meaning which is inferred or implied.[1]

The phrase describes two different ways of understanding the meaning of a situation.[2]

The idiom is used rhetorically to indicate that a particular situation could be a cause for optimism (half full) or pessimism (half empty).[3]


The phrase is a metaphor. For example,

According to musician Jelly Roll Morton, "If a glass of water is full, you can't add any more water, but if you have half a glass, you can always put more water in it -- and jazz music is based on the same principles."[4]

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