| The philosophical idea, put forward by the book by Milan Kundera of the same name, that human life is stripped of meaning, and thus fundamentally "light" and without substance, because we may travel through it only once, and make only one set of choices. "We can never know what we want", he writes, "because, living only one life, we can neither compare it to our previous lives nor perfect it in our lives to come."
This idea has its origins in Friedrich Nietzsche's idea of the "Eternal Return", or "Eternal Recurrence", one of the primary ideas of his Also Sprach Zarathustra. In the Eternal Recurrence, we (re)live each and every moment of our lives over and over again, into eternity. Nietzsche found the prospect of this to be terrifying, calling it das schwerste Gewicht, the heaviest burden.
Kundera's idea is in some sense the obverse of this idea, that nothing returns, that the moments of our lives disappear and the weight and significance of our choices fades along with them. He writes:
We live everything as it comes, without warning, like an actor going on cold. And what can life be worth if the first rehearsal for life is life itself? That is why life is always like a sketch. No, "sketch" is not quite the word, because a sketch is an outline of something, the groundwork for a picture, whereas the sketch that is our life is a sketch for nothing, an outline with no picture.
Note: The novel goes on (arguably, IMHO) to find redeeming qualities in the value of the choices we do make in light of this condition, so it's not as bleak as it sounds. In fact, it's quite uplifting, and thoroughly enjoyable.
Quotes from:The Unbearable Lightness of Being, trans. Michael Henry Hein, Harper&Row, 1984.
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