Natural philosophy or the philosophy of nature (from Latin philosophia naturalis) was the philosophical 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.

From the ancient world, starting with Aristotle, to the 19th century, the term "natural philosophy" was the common term used to describe the practice of studying nature. It was in the 19th century that the concept of "science" received its modern shape with new titles emerging such as "biology" and "biologist", "physics" and "physicist" among other technical fields and titles; institutions and communities were founded, and unprecedented applications to and interactions with other aspects of society and culture occurred.Isaac Newton's book Philosophiae Naturalis Principia Mathematica (1687), whose title translates to "Mathematical Principles of Natural Philosophy", reflects the then-current use of the words "natural philosophy", akin to "systematic study of nature". Even in the 19th century, a treatise by Lord Kelvin and Peter Guthrie Tait, which helped define much of modern physics, was titled Treatise on Natural Philosophy (1867).