The 1935 peer-reviewed article by Stephen C. Pepper in the _Jounral of Philosophy_ foreshadows the publication of the first two chapters of World Hypotheses: A Study in Evidence (1942).
> The root metaphor theory of metaphysics is a theory of the origin and development of metaphysical hypotheses. If correct, it entails certain consequences clarifying not only to the field of metaphysics but to other cognitive fields as well. It involves > * first (1), the proposition that dogmatism is illegitimate and unnecessary in cognitive procedure; > * second (2), that the method of hypothesis is legitimate, and so far as we can see, the only available undogmatic method; and, > * third (3), that one way, and perhaps the only way, in which metaphysical hypotheses can be derived is through the analysis of a selected group of facts (which I call the root metaphor) and the expansion of that analysis among other facts. > The third proposition presupposes the first two, and the second the first; but the first proposition does not involve the other two, nor the second the third. > One may eschew dogmatism and not champion a method of hypothesis, provided one can think of any other undogmatic cognitive method, but one may accept the method of hypothesis and not champion the root metaphor method, provided one can think of any other better hypothetical method by which metaphysical hypotheses may be derived. > I will take the first two propositions up very briefly, for a thorough discussion of them would lead far beyond the bounds of a single paper, and I will spend my time mainly on the third. This paper, then, is an argument in the form: If the first two propositions are true, let me show you that the third proposition also is true-namely, that one way and perhaps the only way of legitimately developing a metaphysical hypothesis is by the root metaphor method. [p. 365, editorial paragraphing added]
## References Pepper, Stephen C. 1935. “The Root of Metaphor Theory of Metaphysics.” _The Journal of Philosophy_ 32 (14): 365–74. https://doi.org/10.2307/2016759.