 Another approach links Goodman’s contrast to the venerable idea that simpler hypotheses are preferable to more complex hypotheses. Induction can be understood (Harman  1973;  White  2005),  as a special case of “inference to the best explanation”, where being “best” is partly a matter of simplicity: the suggestion is that the hypothesis (i.e. the proposition) that all emeralds are green is simpler than the hypothesis that all emeralds are grue. The degree of simplicity of a proposition might simply be identified with its degree of naturalness (see  §3.3  above).[57]