Wikipedia describes Goethe as a writer and Statesman. He was so much more than that. He was a philosopher, he was a poet, he was to Germany what Shakespeare was to England. Only that is True which turns out to be fruitful… this can be interpreted in many ways. For me Goethe implied here that optimistic people who are productive can change the world for the better. They have something to show for their efforts – hence there is a truth in what they do and leave behind. As for the rest that produce nothing – they are simply forgotten. Are you following your true purpose in life?