Natural classification

“ As the first principle of natural classification is that the classes must be so formed that the objects composing each may have as many properties in common as possible to serve as predicates, all kinds should have places among the natural groups, since the common properties of kinds, and, therefore, the general assertions that can be made about them, are innumerable. ”

“ The phrase Natural Classification seems most peculiarly appropriate to such arrangements as correspond, in the groups which they form, to the spontaneous tendencies of the mind, by placing together the objects most similar in their general aspect; in opposition to those technical systems which, arranging things according to their agreement in some circumstance arbitrarily selected, often throw into the same group objects which in the general aggregate of their properties present no resemblance, and into different and remote groups, others which have the closest similarity. ”

“ There is a method, well known to natural science, for measuring and indicating the divergence of man from his nearest allies. This is the application of those principles of classification which, though of essential importance in science, are by some modern students of nature strangely overlooked or misunderstood. Perhaps in nothing has the progress of ideas of evolution made a more injurious impress on the advance of knowledge than in the manner in which it has caused many eminent and able naturalists to diverge from all logical propriety in their ideas of classification. ”

“ Classification is merely an indication of characteristics which are already there. For example, botanical classification by stamens and pistils and petals applies to flowers, but not to men. Thus the space of the consentient set is a fact of nature ”

“ The Classification thus obtained, depends neither upon the faculties of the mind to which the separate parts of our knowledge owe their origin, nor upon the objects which each science contemplates; but upon a more 137 natural and fundamental element;—namely, the Ideas which each science involves. The Ideas regulate and connect the facts, and are the foundations of the reasoning, in each science: and having in another work more fully examined these Ideas, we are now prepared to state here the classification to which they lead. ”

“ It has been usual to distinguish systems of classification as natural and artificial, those being called natural which seemed to express the order of existing things as determined by nature. Artificial methods of classification, on the other hand, included those formed for the mere convenience of men in remembering or treating natural objects. ”

“ Perplexed by the difficulties arising in natural history from the discovery of intermediate forms, naturalists have resorted to what they call classification by types. Instead of forming one distinct class defined by the invariable possession of certain assigned properties, and rigidly including or excluding objects according as they do or do not723 possess all these properties, naturalists select a typical specimen, and they group around it all other specimens which resemble this type more than any other selected type. ”

“ The two systems of classification—natural and artificial—having been distinguished, the natural system is defined as having for its object the classification of plants according to their fundamental relationships; and these being established once for all by Nature herself, it is not based on any arbitrary principle, but depends upon the state of our knowledge of these fundamental relationships. ”

“ When Natural History again came to be studied in Nature, the business of Classification, as we have seen, forced itself upon men’s attention, and was pursued with interest in animals, as in plants. The steps of its advance were similar in the two cases;—by successive naturalists, various systems of artificial marks were selected with a view to precision and convenience;—and these artificial systems assumed the existence of certain natural groups, and of a natural system to which they gradually tended. ”

“ We can understand why a classification founded on any single character or organ—even an organ so wonderfully complex and important as the brain—or on the high development of the mental faculties, is almost sure to prove unsatisfactory. This principle has indeed been tried with hymenopterous insects; but when thus classed by their habits or instincts, the arrangement proved thoroughly artificial.257 Classifications may, of course, be based on any character whatever, as on size, colour, or the element inhabited; but naturalists have long felt a profound conviction that there is a natural system. ”

“ In other words, while forming their artificial systems of classification, it has always been the aim of naturalists—whether consciously or unconsciously—to admit as the bases of their systems those characters which, in the then state of their knowledge, seemed most calculated to play an important part in the eventual construction of the natural system. ”

“ If human thought proceeded with the orderly method which abstract logic would suggest to it, we might go further and say that a classification of natural entities should be the first step in science itself. Perhaps you will be inclined to reply that this classification has already been effected, and that science is concerned with the adventures of material entities in space and time. ”

“ All attempts at a scientific classification of animals, since first their anatomy and physiology were successfully studied, have been framed with a certain degree of instinctive reference to a natural series, and have accorded in many more points than they have differed, with the classification which would most naturally have been grounded on such a series. ”

“ Thus we arrive at the great classifications of natural science, with which every one is more or less familiar. But the works of men have their classification too, for in human effort like causes produce like effects. ”

“ Classification of Functions.—Attempts to classify the Vital Functions of man were made at an early period, and have been repeated in great number up to modern times. The task of classification is exposed to the same difficulties, and governed by the same conditions, in this as in other subjects. Here, as in the case of other things, there may be many classifications which are moderately good and natural, but there is only one which is the best and the true natural system. ”

“ The very impossibility of grouping phenomena into natural kinds renders an artificial classification necessary. Before science can advance a single step, the innumerable phenomena of nature must be reduced into classes. ”

“ Such Ideas in botany have influenced the progress of the science, even before they have been clearly brought into view. We have especially the Idea of Affinity, which is the basis of all Natural Systems of Classification, and which we shall consider in a succeeding chapter. The assumption that there is a Natural System, an assumption made by all philosophical botanists, implies a belief in the existence of Natural Affinity, and is carried into effect by means of principles which are involved in that Idea. ”

“ With reference to the question, whether these groups really exist in Nature or are merely the expression of individual theories and opinions, it is worth while to study the works of the early naturalists, in order to trace the natural process by which scientific classification has been reached ”

“ This discovery is made by means of comparison and classification. We cease to study each flower for its own sake; and by continually enlarging the sphere of our observation, we try to discover what is common to many and offers those essential points on which groups or natural classes may be established. These classes again, in their more general features, are mutually compared; new points of difference, or of similarity of a more general and higher character, spring to view, and enable us to discover classes of classes, or families. ”

“ Classification, groups subordinate to groups—Natural system—Rules and difficulties in classification, explained on the theory of descent with modification—Classification of varieties—Descent always used in classification—Analogical or adaptive characters—Affinities, general, complex and radiating—Extinction separates and defines groups—Morphology, between members of the same class, between parts of the same individual—Embryology, laws of, explained by variations not supervening at an early age, and being inherited at a corresponding age—Rudimentary Organs ”

“ In this way the second or classificatory leads us naturally to the third or final stage—the theoretical, or metaphysical. If the work of classification is properly carried out, it teaches us that nothing exists in nature by accident; that each individual belongs to a species, each species to a genus ”

“ What interpretation is to be put on these truths of classification? We find that organic forms admit of an arrangement everywhere indicating the fact, that along with certain attributes, certain other attributes, which are not directly connected with them, always exist. How are we to account for this fact? And how are we to account for the fact that the attributes possessed in common by the largest assemblages of forms, are the most vitally-important attributes? ”

“ Logically speaking, we ought to leave a place open for animals which ruminate but are without cleft feet, and for every possible intermediate form of animal, plant, or mineral. A purely logical classification must take account not only of what certainly does exist, but of what may in after ages be found to exist. ”

“ Every age manages to find modes of classification which seem fundamental starting points for the researches of the special sciences, Each succeeding age discovers that the primary classifications of its predecessors will not work. In this way a doubt is thrown upon all formulations of laws of Nature which assume these classifications as firm starting points. ”

“ Here, then, we have an empirically discovered rule in the science of classification, the raison d’être of which we are at once able to appreciate upon the theory of evolution, whereas no possible explanation of why it should ever have become a rule could be furnished upon the theory of special creation. ”

“ It is the essence of the method of the naturalist. How he applies it first to one character, and then to another, and finally obtains a notion of a species of animals, the differences between whose members, however great, are confined within limits, is a matter which does not here concern us. The whole method of classification must be considered later; but, at present, I only desire to point out that it is by taking advantage of the idea of continuity, or the passage from one form to another by insensible degrees, that the naturalist builds his conceptions. ”

“ All that is not strictly definition, that is, all that is not artificial character, in the descriptions of such classes, is a statement of truths, more or less general, more or less precise, but making up, together, the positive knowledge which constitutes the science. As we have said, the consideration of the properties of plants in order to form a system of classification, has been termed Taxonomy, or the Systematick of Botany ”

“ According to the theory of evolution (worked out since Mill wrote) , Kinds—that is, species of plants, animals and minerals—with their qualities are all due to causation. Still, as we can rarely, or never, trace the causes with any fullness or precision, a great deal of our reasoning, as, e.g., about men and camels, does in fact trust to the relative permanence of natural Kinds as defined by co-inhering attributes. ”

“ Throughout, however, there must necessarily exist a certain classification of things according to their properties—a classification which is either organically registered in the system, as in the inferior creation, or is formed by experience, as in ourselves. ”

“ Thus we perceive that in forming their provisional or artificial classifications, naturalists have been guided by an instinctive belief in some general principle of natural affinity, the character of which they have not been able to define ”

“ When we look beyond this large and general fact of all the innumerable forms of life being thus united in a tree-like system by an unquestionable relationship of some kind, to those smaller details in the science of classification which have been found most useful as guides for this kind of research, then we find that all these details, or empirically discovered rules, are exactly what we should have expected them to be, supposing the real meaning of classification to have been that of tracing lines of pedigree. ”

“ I pass over the process of classification, which itself requires a great deal of scientific thought, in particular when a naturalist, who has studied and monographed a fauna or a flora rather than a family, is able at once to pick out the distinguishing characters required for the subdivision of an order quite new to him. Suppose that we possess all this minute and comprehensive knowledge of plants and animals and intermediate organisms, their affinities and differences, their structures and functions—a vast body of experience, collected by incalculable labor and devotion. ”

“ To those who accept the general doctrine of Evolution, it need scarcely be pointed out that classifications are subjective conceptions, which have no absolute demarcations in Nature corresponding to them. ”

“ As observation becomes more minute, and the mind advances in culture and power of discrimination, these ruder generalizations are either abandoned or subdivided into genera and species, and the process assumes a scientific form. What was at first mere classification, becomes now, in the strictest sense, generalization.
Scientific Classification.—Classification, however scientific, is still essentially the process already described. We observe a number of individuals, for example, of our own species. Certain resemblances and differences strike us. ”