German naturalist who was a leader in the Naturphilosophie movement. Oken's views were mystical, including speculations on nothing, something, motion, God, and the geometric form of the universe. His prolific speculations, however, foreshadowed cell theory, as in the idea that all tissues were composed of a "fundamental polyp," or "infusorian."

He described the force of attraction between the Sun and Earth, as well as light, as tension in ether.