period when observation is determined by experimental conditions depending upon the use of certain guiding conceptions; when reflection is directed and checked at every point by the use of experimental data, and by the necessity of finding such a form for itself as will enable it to serve in a deduction leading to evolution of new meanings, and ultimately to experimental inquiry which brings to light new facts. In the emerging of a more orderly and significant region of fact, and of a more coherent and self-luminous system of meaning, we have the natural limit of evolution of the logic of a given science. But consider what has happened in this historic record. Unanalyzed experience has broken up into distinctions of facts and ideas; the factual side has been developed by indefinite and almost miscellaneous descriptions and cumulative listings; the conceptual side has been developed by unchecked and speculative elaboration of definitions, classifications, etc. Then there has been a relegation of accepted meanings to the limbo of mere ideas; there has been a passage of some of the accepted facts into the region of mere hypothesis and opinion. Conversely, there has been a continued issuing of ideas from the region of hypotheses and theories into that of facts, of accepted objective and meaningful objects. Out of a world of only _seeming_ facts, and of only _doubtful_ ideas, there emerges a world continually growing in definiteness, order, and luminosity. This progress, verified in every record of science, is an absolute monstrosity from the standpoint of the epistemology which assumes a thought in general, on one side, and a reality in general, on the other. The reason that it does not present itself as such a monster and miracle to those actually concerned with it is because _continuity_ of reference and of use controls all diversities in the modes of existence specified and the types of significance assigned. The distinction of meaning and fact is treated in the growth of a science, or of any particular scientific problem, as an _induced_ and _intentional_ practical division of labor; as assignments of relative position with reference to performance of a task; as deliberate distribution of forces at command for their more economic use. The absorption of bald fact and hypothetical idea into the formation of a single world of scientific apprehension and comprehension is but the successful achieving of the aim on account of which the distinctions in question were instituted.