"One" anaphora (e.g., "this is a good one") has been used as a key diagnostic in syntactic analyses of the English noun phrase, and "'one'-replacement" has also figured prominently in debates about the learnability of language. However, much of this work has been based on faulty premises, as a few perceptive researchers, including Ray Jackendoff, have made clear. Abandoning the view of anaphoric "one" ("a-one") as a form of syntactic replacement allows us to take a fresh look at various uses of the word "one." In the present work, we investigate its use as a cardinal number ("1-one") in order to better understand its anaphoric use. Like all cardinal numbers, "1-one" can only quantify an individuated entity and provides an indefinite reading by default. Owing to unique combinatoric properties, cardinal numbers defy consistent classification as determiners, quantifiers, adjectives, or nouns. Once the semantics and distribution of cardinal numbers, including "1-one," are appreciated, many properties of "a-one" follow with minimal stipulation. We claim that "1-one" and "a-one" are distinct but very closely related lexemes. When "1-one" appears without a noun (e.g., "'Take' one"), it is nearly indistinguishable from "a-one" (e.g., "take 'one'")--the only differences being interpretive ("1-one" foregrounds its cardinality while "a-one" does not) and prosodic (presence versus absence of primary accent). While we ultimately argue that a family of constructions is required to describe the full range of syntactic contexts in which "one" appears, the proposed network accounts for properties of "a-one" by allowing it to inherit most of its syntactic and interpretive constraints from its historical predecessor, "1-one."