the type and principles both of the problem and of its answer. The details of the particular answer are the “_matter_ of fact.” The type and principles which are found in all such particular answers may be regarded as the form of fact, _i.e._ that which makes the fact a fact in knowledge. Jevons appears to me to make a terrible blunder at this {45} point. He says [1]--“One name which has been given to Logic, namely the Science of Sciences, very aptly describes the all-extensive power of logical principles. The cultivators of special branches of knowledge appear to have been fully aware of the allegiance they owe to the highest of the sciences, for they have usually given names implying this allegiance. The very name of Logic occurs as part of nearly all the names adopted for the sciences, which are often vulgarly called the ‘ologies,’ but are really the ‘logics,’ the ‘o’ being only a connecting vowel or part of the previous word. Thus geology is logic applied to explain the formation of the earth’s crust; biology is logic applied to the phenomena of life; psychology is logic applied to the nature of the mind; and the same is the case with physiology, entomology, zoology, teratology, morphology, anthropology, theology, ecclesiology, thalattology, and the rest. Each science is thus distinctly confessed to be a special logic. The name of Logic itself is derived from the common Greek word λόγος, which usually means _word_, or the sign and outward manifestation of any inward thought. But the same word was also used to denote the inward thought or reasoning of which words are the expression, and it is thus probably that later Greek writers on reasoning were led to call their science ἐπιστήμη λογική, or logical science, also τέχνη λογική or logical art. [2] The adjective λογική, being used alone, soon came to be the name of the science, just as Mathematic, Rhetoric, and other names ending in ‘ic’ were originally adjectives, but have been converted into substantives.” [1] _Elementary Lessons_, p. 6. [2] [= “logos”, “episteme logike”, “techne logike” and “logike”. Tr.]