When the philosopher Karl Jaspers was a child in the late 1800s, his father took him to the Frisian Islands in the North Sea. One day they walked holding hands across the wet sand. Jaspers recalls, “The tide was out, our path across the fresh, clean sand was amazing, unforgettable for me, always further, always further, the water was so low, and we came to the water, there lay the jellyfish, the starfish—I was bewitched.”