In World Hypotheses: A Study in Evidence (1942), Chapter V: Root Metaphors, §3, Pepper presents a common sense way that an individual person might understand the world
digraph PepperCh05RootMetaphorMethod { // Global setup rankdir = TB // Node list {rank=same man loo} man [shape=box color="green" label="A man\ndesiring to\nunderstand\ntheworld"] loo [shape=oval color="blue" label="Looking about\nfor a clue\nto comprehend\nthe world"] {rank=same pit rm} pit [shape=oval color="blue" label="Pitching upon\nsome area of\ncommonsense fact"] rm [shape=box color="green" label="Root\nMetaphor"] {rank=same ds sf} ds [shape=oval color="blue" label="Discriminating\nStructure"] sc [shape=box color="green" label="Set of\nCategories"] sf [shape=oval color="blue" label="Studying\nOther Areas\nof Fact"] // Adding edges man -> loo [arrowhead="dot" label="handles"] loo -> pit [arrowhead="lvee" label="invokes"] pit -> rm [arrowhead="onormal" arrowsize="0.8" label="yields"] rm -> ds [dir=both arrowtail="onormal" arrowhead="onormal" arrowsize="0.8" label="affects"] ds -> sc [dir=both arrowtail="onormal" arrowhead="onormal" arrowsize="0.8" label="affects"] man -> ds [arrowhead="dot" label="handles"] sf -> ds [arrowhead="onormal" arrowsize="1.5" label="is part of\n(consists)"] sf -> sc [dir=both arrowtail="onormal" arrowhead="onormal" arrowsize="0.8" label="affects"] }
> §3. _The root-metaphor method_ -- So we return to the traditional analogical method of generating world theories. The method in principle seems to be this: > * A man desiring to understand the world looks about for a clue to its comprehension. > * He pitches upon some area of commonsense fact and tries if he cannot understand other areas in terms of this one. This original area becomes then his basic analogy or root metaphor. > * He describes as best he can the characteristics of this area, or, if you will, discriminates its structure. > * A list of its structural characteristics becomes his basic concepts of explanation and description. We call them a set of categories. > * In terms of these categories he proceeds to study all other areas of fact whether uncriticized or previously criticized. He undertakes to interpret all facts in terms of these categories. > * As a result of the impact of these other facts upon his categories, he may qualify and readjust the categories, so that a set of categories commonly changes and develops. > Since the basic analogy or root metaphor normally (and probably at least in part necessarily) arises out of common sense, a great deal of development and refinement of a set of categories is required if they are to prove adequate for a hypothesis of unlimited scope. > Some root metaphors prove more fertile than others, have greater powers of expansion and of adjustment. These survive in comparison with the others and generate the relatively adequate world theories. [pp. 91-92, editorial paragraphing added]
Pepper traces a (since deprecated) metaphor as a parable for structural hypotheses and root metaphors, in pre-Socratic philosophy and science. The Milesian School was the First Self-Conscious World Theory in European Thought where was water seen as the primary element.