Natural philosophy is a branch of metaphysical philosophy treating the natural world, that is, real entities belonging to grades of being inferior in power to man, the angels and God.
"Metaphysical" is a word meant to distinguish an anciently established division between two different types of knowledge. In Western Civilization's earliest surviving complete philosophical work, the Charmides by Plato, the distinction is drawn between bodies of knowledge that produce a practical result, and those that do not. Natural philosophy has been categorized as a theoretical, speculative or "metaphysical" rather than a practical branch of philosophy (like, for example, ethics). Bodies of knowledge that guide arts and draw upon the philosophical knowledge of nature may produce practical results, but these subsidiary sciences (e.g. architecture or medicine) go beyond natural philosophy.
Methods of natural philosophy
Natural philosophers render account of nature by
- observing and describing nature including the gathering of observations and descriptions of others
- attempting measurements of physical quantities in order to compare and contrast various phenomena
- arranging reasonings from known facts into arguments, attempting to prove or explain things less known, while refining definitions of the arguments' mediating ideas to ensure the judgments composing the arguments work together logically
- testing one's arguments by applying them to further cases and comparing them against the ideas of others.
Origins of natural philosophy
Western natural philosophy began with eminent Greek pre-Socratic philosophers such as Thales, Anaximander, possibly Pythagoras, Heraclitus, Anaxagoras, Empedocles and Philolaus, many of whom were involved in various schools. For example, Anaximander and Thales belonged to the Milesian school. Plato, briefly and Aristotle at length, in works that survived to today, continued these studies of nature.
Presuppositions of natural philosophy
Natural philosophy presupposes that change is a reality. Although this may seem obvious, there have been some philosophers who have denied the concept of change, such as Plato's predecessor Parmenides and later Greek philosopher Sextus Empiricus, and perhaps some Eastern philosophers. George Santayana, in his Scepticism and Animal Faith, attempted to show that the reality of change cannot be proven. If his reasoning is sound, it follows that to be a physicist, one must restrain one's skepticism enough to trust one's senses.
Branches and subject matter of natural philosophy
Major branches of natural philosophy include astronomy and cosmology, the study of nature on the grand scale; etiology, the study of (intrinsic and sometimes extrinsic) causes; the study of chance, probability and randomness; the study of elements; the study of the infinite and the unlimited (virtual or actual); the study of matter; mechanics, the study of translation of motion and change; the study of nature or the various sources of actions; the study of natural qualities; the study of physical quantities; the study of relations between physical entities; and the philosophy of space and time.
Natural philosophy and science
Natural philosophy also was a name that applied to scientific rather than purely philosophical study which was used extensively before the 19th century.
The term scientist only emerged in the 19th century. Prior to this, scientific study was called natural philosophy and scientists were natural philosophers. These disciplines entailed broad areas of study of the universe, employing mathematics and the scientific method in the sciences of chemistry, physics, anatomy, and so forth.