“Natural philosophy” was the term used to describe what we now call science. The key players in the scientific revolution, beginning with Galileo (1564–1642) and ending with Isaac Newton (1643–1727), were called “natural philosophers” and were revered as geniuses by philosophers of their day. The lines between scientific inquiry, philosophical theories of knowledge, and philosophy of science were not clearly drawn until these “natural philosophers’“ discoveries and theories helped define them.