James et al. "An Introduction to Statistical Learning" (2013) p. 29 states:
There is no free lunch in statistics: no one method dominates all others over all possible data sets. On a particular data set, one specific method may work best, but some other method may work better on a similar but different data set.
The focus on data sets leaves an ambiguity as to whether the no free lunch phenomenon is due to
(1) random sampling from any given data generating process (DGP) or population, resulting in samples with different properties/patterns or
(2) the variety of possible DGPs and populations that are being modelled.
My understanding is that the no free lunch theorem concerns (2) rather than (1).
Quesion: Would it not be more precise and accurate to replace "data sets" with "data generating processes" in the passage?