Physics
The Root That Named Existence
At the foundation of Indo-European speech lies a root so ancient and so productive that it gave different branches of the family not only their word for *being* but their word for *science itself*. The PIE root *\*bʰuH-* meant something like "to come into being, to grow, to become" — a verb for the process of existence rather than its static state. Every daughter language took this root and did something different with it, and the divergence is a lesson in how culture shapes the words a people keep.
In Old English, *\*bʰuH-* became *bēon*, the verb *to be* — specifically the habitual and future forms: *ic bēo* ("I am, I shall be"). Modern English still preserves this in *be*, *been*, *being*. In Latin, the same root gave *fui* ("I was", perfect of *esse*) and the future participle *futurus* — the thing that is *becoming*, which English borrowed as *future*. In Sanskrit, it became *bhū* ("to be, to become"), which generated *Bhūmi* ("earth, the ground of being") and ultimately appears in the name *Bhutan*, meaning roughly "land of being" or "high ground". In Greek, *phyein* took on the specifically biological sense of *growing* — the thing that plants do, that bodies do, that nature does.
From *phyein*, Greek built *physis* (φύσις): the process of growth, the nature of a thing, the whole order of the natural world. This is not a word chosen by accident. When early Greek thinkers turned their attention to the material world — to why things fall, why fire rises, why plants grow toward light — they reached for the word that meant *growth and becoming*. The inquiry into *physis* was an inquiry into process, not mere substance.
Aristotle's Manuscript Order
The word *metaphysics* contains a small historical joke. Aristotle wrote a group of texts on first principles and the nature of being. When his editors compiled his works, these texts were placed in the manuscript *after* (Greek *meta*) his texts on *physis* — the natural world. So *ta meta ta physika* means nothing more philosophical than "the books that come after the physics books". The name stuck, and later readers assumed Aristotle had intended a grand hierarchy of knowledge, with metaphysics floating above physics as its foundation. He had not. He had simply filed things.
But *ta physika* itself — "the natural things" — was already a title shaped by *physis*. Aristotle's physics was the science of things that *grow and change of themselves*, as distinct from artifacts, which are made by external hands.
Physician and Physicist
The same Greek *physis* gave Latin *physica* (knowledge of nature) and *physicus* (one who studies nature). In medieval Europe, *physica* meant natural science broadly — but also, specifically, medicine, because medicine was the practical application of knowing how bodies naturally work. A *physician* is therefore a *nature-knower*: someone trained in the principles of how living things grow and fail.
For centuries, *physics* and *medicine* were not clearly distinguished. In early modern English, a *physician* was a *physicker* — one who applies natural knowledge. The two branches of the same word separated only as specialization deepened.
Newton did not call his great work *Physics*. He called it *Philosophiae Naturalis Principia Mathematica* — the mathematical principles of natural philosophy. To Newton, physics was still *natural philosophy*: inquiry into *physis* by rational method. The shift from "natural philosophy" to "physics" as the discipline's name came only in the nineteenth century, as the field became professionalized and mathematized to a degree that separated it from broader philosophical inquiry.
One Root, Two Extremes
The deepest irony of this family is the distance between its endpoints. The word *be* — the most minimal, abstract, grammatically indispensable word in English — and the word *physics* — the name of the most precisely mathematical natural science — are the same word. They share PIE *\*bʰuH-* as their common ancestor.
Greek took the root in the direction of *growth and nature*; Germanic took it in the direction of *bare existence*. Physics, then, named itself not after matter or force or energy, but after *becoming* — after the Greek sense that what is real is what grows and changes. There is a philosophy embedded in the etymology: the science of physics was always, at its Greek source, the science of *becoming*, not merely *being*.