open texture

Etymology
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Noun

 * 1)  A philosophical concept that refers to the universal possibility of imprecision in empirical statements.
 * 2)  The phenomenon that legal rules are a function of language and are thus subject to attempts at definition of vague or interpretative terms.

Usage notes
The philosophical concept of open texture differs slightly from that of vagueness. For instance, the term "mother" is not vague, but can be made to seem imprecise (read "open-textured") if one draws a distinction between the mother who produces the ovum, the one who carries the fetus, and the one who delivers the baby.