This word “form” is always meeting us in philosophy. “Species” is Latin for form, as εἶδος and ἰδεα [1] are Greek for form. The form of any object primarily means its appearance, that which the mind can carry away, while the object as a physical reality, as material, remains where it was. It need not mean shape as opposed to colour; that is a narrower usage. The Greek opinion was no doubt rooted in some such notion as that in knowing or remembering a thing the mind possessed its form or image without its matter. Thus the form came to stand for the knowable shape or structure which makes a thing what it is, and by which we recognise it when we see it. This was its species or its idea, the “image,” as it is used in the phrase, “Let us make man in our own image.” So in any work of the hands {43} of man, the form was the shape given by the workman, and came out of his mind, while the matter was the stuff or material out of which the thing was made.
[1] [= “eidos” and “idea”. Tr.]
The moment we contemplate a classification of the sciences, we see that this is a purely relative distinction. There is no matter without form. If it was in this deep sense without form, it would be without properties, and so incapable of acting or being acted upon. In a knife the matter is steel, the form is the shape of the blade. But the qualities of steel again depend, we must suppose, upon a certain character and arrangement in its particles, and this is, as Bacon would have called it, the form of steel. But taken as purely relative, the distinction is good prima facie. Steel has its own form, but the knife has its form, and the matter steel can take many other forms besides that of a knife. Marble has its own form, its definable properties as marble (chemical and mechanical), but in a statue, marble is the matter, and the form is the shape given by the sculptor.
Now applying this distinction to knowledge in general, we see that all science is formal, and therefore it is no distinction to say that Logic is a formal science. Geometry is a formal science; even molecular physics is a formal science. All science is formal, because all science consists in tracing out the universal characteristics of things, the structure that makes them what they are.
The particular “form,” then, with which a science deals is simply the kind of properties that come under the point of view from which that science in particular looks at things. But a very general science is more emphatically formal than {44} a very special science. That is to say, it deals with properties which are presented in some degree by everything; and so in every object a great multitude of properties are disregarded by it, are treated by it as matter and not as form. In this sense Logic is emphatically “formal,” though not nearly so formal as it is often supposed to be. The subject-matter of Logic, then, is Knowledge qua Knowledge, or the form of knowledge; that is, the properties which are possessed by objects or ideas in so far as they are members of the world of knowledge. And it is quite essential to distinguish the form of knowledge in this sense from its matter or content. The “matter” of knowledge is the whole region of facts dealt with by science and perception. If Logic dealt with this in the way in which knowledge deals with it, i.e. simply as a process of acquiring and organising experience, then Logic would simply be another name for the whole range of science, history, and perception. Then there would be no distinction between logic and science or common sense, and in trying to ascertain, say, the wave-length of red light, or the cab-fare from Chelsea to Essex Hall, we should be investigating a logical problem. But we see at once that this is not what we mean by studying knowledge as knowledge. Science or common sense aims at a particular answer to each problem of this kind. Logic aims at understanding 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.]
{46} This account of the connection between the name “Logic” and the terminations of the names of the sciences appears precisely wrong. Whatever may have been the exact meaning of the expression “Logic,” or “Logical curriculum,” [1] or “art,” or “science” when first employed, there can be no doubt that the word logical had a substantive reference to that about which the science or teaching in question was to treat. The term “logic,” therefore, corresponds not to the syllables “logy” in such a word as “Zoology,” but to the syllables “Zoo,” which indicate the province of the special science, and not its character as a science. Zoology means connected discourse (λόγος) about living creatures. Logic meant a curriculum, or science or art dealing with connected discourse. The phrase “Science of Sciences,” rightly interpreted, has the same meaning. It does not mean that Logic is a Science which comprises all the special sciences, but that Logic is a Science dealing with those general properties and relations which all sciences qua sciences have in common, but omitting, as from its point of view matter and not form, the particular details of content by which every science answers the particular questions which it asks. It is wild, and most mischievous, to say that “every science is a special logic,” or that “biology is Logic applied to the phenomena of life.” This confusion destroys the whole disinterestedness which is necessary to true scientific Logic, and causes the logical student always to have his eye on puzzles, and special methods, and interferences by which he may teach the student of science how to perform the concrete labour of research. We quite admit that {47} a looker-on may sometimes see more of the game, and no wise investigator would contemn a priori the suggestions of a student like Goethe, or Mill, or Lotze, because their author was not exclusively engaged in the observation of nature. But all this is secondary. The idea that Logic is a judge of scientific results, able to pass sentence, in virtue of some general criterion, upon their validity and invalidity, arises from a deep-lying misconception of the nature of truth which naturally allies itself with the above confusion between Logic and the special sciences.
[1] πραγμάτεια [= pragmateia Tr.]. See Prantl, i. 545.