Natural philosophy or the philosophy of nature (from Latin philosophia naturalis) was the study of nature and the physical universe that was dominant before the development of modern science. It is considered to be the precursor of natural sciences such as physics.

Forms of science historically developed out of philosophy or, more specifically, natural philosophy. At older universities, long-established Chairs of Natural Philosophy are nowadays occupied mainly by physics professors. Modern notions of science and scientists date only to the 19th century. The naturalist-theologian William Whewell was the one who coined the term "scientist". The Oxford English Dictionary dates the origin of the word to 1834. Before then, the word "science" simply meant knowledge and the label of scientist did not exist. Some examples of the term's usage are Isaac Newton's 1687 scientific treatise is known as The Mathematical Principles of Natural Philosophy and Lord Kelvin and Peter Guthrie Tait's 1867 treatise called Treatise on Natural Philosophy which helped define much of modern physics.