A score of 1 million is impossible. The highest score on record is 227. We have no way of saying what the maximum score could be. This set of all possible scores is thus ill-defined. Hockett asserts that no physical system is well-defined.
Physical systems have moving parts.
If the system is not isolated, then unforeseeable influences from outside will impinge, whose effects are again only statistically predictable. Consider the relationship between hydrocarbon molecules of the methane series, and the structural formulae which describe the hydrocarbons. Arrange the C' sin a row and insert a line segment after each bu the last. The set of formulae is well-defined, and infinite. Not so the hydrocarbons themselves.