Probability is an absolute scale. Bayes' Law and other axioms depend on absolute scaling. Just as a difference of intervals is ratio, some divisions of ratios produce absolute measures. Counts are discrete, since only integers can result. There is a real zero, and 2x does mean twice the quantity.
Some measures are cyclical, with a fixed range.
Multidimensional measures Multidimensional scales have extra relationships. In Stevens' scheme, an unbounded linear axis could not be fit into a fixed interval without losing information. Hence, test for equivalence only. The four levels are not adequate. Nominal must be expanded Extensive and derived must be distinguished Higher levels recognized Multidimensional relationships handled Measurement involves more axioms than just those involved in the number line.