When I teach Behavior Modification, I tell my students that they are learning how to serve as a “bridge over troubled waters.” My words include a metaphor —  a figure of speech that is not literally true.

Metaphors have long been an important part of writing and speaking. Think of the Bible, Isaiah 64:8: “O Lord, You are our Father, We are the clay, and You our potter.”  We not actually clay; God is not literally our father.

Poets love metaphor. Ponder this statement by poet William Butler Yeats: “Education is not the filling of a pail, but the lighting of a fire.”

Playwrights join in also. One of the most famous metaphors ever is: “All the world’s a stage, and all the men and women merely players.” Here Shakespeare points out that we enact roles in specific situations. He was an early social psychologist.

Sometimes artists speak in metaphors. Pablo Picasso said: “Art washes away from the soul the dust of everyday life.”

Scientists are usually not great speakers or writers, but astronomer Fred Hoyle hit the jackpot with his derisive characterization of the explosive start of the universe as a Big Bang. The term stuck. It is as popular as the sitcom named after it, The Big Bang Theory. The term is metaphor because there was nothing at the start to carry sound waves.

We see that metaphors need not be precisely correct. If they carry a valuable idea in a memorable package, they survive.

Think of these song lyrics:  “How does it feel to be on your own, like a rolling stone?” Metaphors like that won Bob Dylan the Nobel Prize in Literature.

Great thinkers do not only speak in metaphors, they think in them – reasoning by analogy. For instance, many individuals, seeing the value in family life, extended the idea of family to a much larger group and created communes, some religious, some not.

Other great thinkers, seeing the value of religious groups but not believing in a deity, founded secular churches – similar in most ways to regular churches but without the worship of a god.

As it turned out, the communes and secular churches have not done well so far. These analogue groups have not quite captured the reality of human needs and behavior.  But I salute the reasoning behind them.

What are your favorite metaphors? What makes them special?