unchanging

Unchanging is an adjective used to describe something that does not change—either in time, form, or condition. It denotes a lack of variation, with states remaining the same under specific constraints or across a range of circumstances. The term is applied across disciplines to distinguish fixed properties from those that are variable.

In science and mathematics, unchanging properties are often called invariants or constants. An invariant remains the same when a system undergoes transformation, while a mathematical constant such as pi or e retains the same value in all contexts. In physics, certain quantities, like the speed of light in vacuum, are treated as unchanging under standard formulations, though real-world conditions can introduce limits to this idealization.

In philosophy and theology, immutability refers to the idea that some essences or beings are not subject to alteration. This is especially prominent in discussions of divine nature, where God is often described as unchanging. Debates also address whether change is real or illusory, and how immutability can be reconciled with notions of providence, freedom, or becoming in other frameworks.

In everyday usage, unchanging can describe long-standing habits, landscapes, or beliefs that persist over time. The term is frequently used descriptively rather than prescriptively, signaling persistence rather than judgment.

Etymology and related terms: the word combines the prefix un- with changing, formed to indicate lack of change. Related concepts include constant, invariant, fixed, and perpetual; opposites include changing, mutable, and variable.