Why is the phrase “other things being equal” used when one generalizes, is developing causal arguments, or is engaged in theory building?

In this essay I pay particular attention to some of the strategies for learning that are implied by the phrase “other things being equal”. I will begin with a common situation where a scientist offers generalizations from data and or experiences that were judged to be interesting, provocative, and or even germane beyond the case and/or particular experiences which prompted their consideration. One should recognize that such products would, of necessity, be “subjectively” derived generally thru inductive reasoning. Such reasoning is organized by their author, based on the knowledge and experience of that author. The logic or integration of such knowledge and experience was also a product of that author.