We hear the phrase "leap of faith" all the time. It refers to a momentous decision we must make that lies outside reason, or one that forces us to grapple with a difficult belief or moral position.

Surprisingly, the phrase isn't very old.

The idea first appears in Soren Kierkegaard's book, Fear and Trembling, which he wrote under the pseudonym Johannes de Silentio.

Let's take a closer look at the phrase "leap of faith," and see what Kierkegaard meant by it.