All pursuit of knowledge used to be one thing: Philosophy. All hypotheses, theories, experiments, observations, discussions of Socrates, Aristotle, Marcus Aurelius, Adi Shankara, Aryabhatta, Confucius, Tao, Ptolemy or anyone fell under one umbrella: Philosophy. Everyone who could read was to some extent religious. In a way, that's how religions were born. They were an effort to formalize the way one should lead their lives, with a sprinkle of practical knowledge here and there in the books.