Life can only be understood backwards; but it must be lived forwards.
The theologian and philosopher Soren Kierkegaard is widely considered to be the creator of existentialism. His studies led him to the idea that reflecting on our past and learning from previous experiences helps us understand our place in the world. Still, life must not be lived in the past. This quote warns us not to dwell on past regret or resentment. We have to let go in order to move forward — which is the only direction life can go.