Some more of Whewell on classification

This is a kind of note to myself, an aide memoire to remind me of the fact that much of the modern narrative about classification in biology before Darwin is not correct. It's also interesting that Whewell defines systematics, but most interesting is the reinforcement of the prior note that Whewell did not support essentialism. Elsewhere, in the History, he famously said that species do not transmute because they have a real existence in nature - but in context he means that they are adapted, and if they varied would cease to be. Again, no mention of essentialism. Whewell is turning out to be a very interesting guy...

From his “Aphorisms concerning ideas”, in The Philosophy of the Inductive Sciences, vol. 2, 1847, pages 459-461. The Roman numerals in brackets link to the book and chapter of the discussion. Below the fold:

LXXXIII.

We collect individuals into Kinds by applying to them the Idea of Likeness. Kinds of things are not determined by definitions, but by this condition;—that general assertions concerning such kinds of things shall be possible, (VIII. 1.)

LXXXIV.

The Names of kinds of things are governed by their use; and that may be a right name in one use which is not so in another. A whale is not a fish in natural history, but it is a fish in commerce and law. (VIII. 1.)

LXXXV.

We take for granted that each kind of things has a special character which may be expressed by a Defini[460]tion. The ground of our assumption is this;—that reasoning must be possible, (VIII. 1.)

LXXXVI.

The "Five Words," Genus, Species, Difference, Property, Accident, were used by the Aristotelians, in order to express the subordination of kinds, and to describe the nature of definitions and propositions. In modern times, these technical expressions have been more referred to by Natural Historians than by Metaphysicians, (VIII. 1.)

LXXXVII.

The construction of a Classificatory Science includes Terminology, the formation of a descriptive language; —Diataxis, the Plan of the System of Classification, called also the Systematick;—Diagnosis, the Scheme of the Characters by which the different Classes are known, called also the Characteristick. Physiography is the knowledge which the System is employed to convey. Diataxis includes Nomenclature, (VIII. 2.)

LXXXVIII.

Terminology must be conventional, precise, constant; copious in words, and minute in distinctions, according to the needs of the science. The student must understand the terms, directly according to the convention, not through the medium of explanation or comparison, (VIII. 2.)

LXXXIX.

The Diataxis, or Plan of the System, may aim at a Natural or an Artificial System. But no classes can be absolutely artificial, for if they were, no assertions could be made concerning them. (VIII. 2.)

[461]

XC.

An Artificial System is one in which the smaller groups (the Genera) are natural; and in which the wider divisions (Classes, Orders) are constructed by the peremptory application of selected Characters; (selected, however, so as not to break up the smaller groups.) (VIII. 2.)

XCI.

A Natural System is one which attempts to make all the divisions natural, the widest as well as the narrowest; and therefore applies no characters peremptorily. (VIII. 2.)

XCII.

Natural Groups are best described, not by any definition which marks their boundaries, but by a Type which marks their center. The Type of any natural group is an example which possesses in a marked degree all the leading characters of the class, (VIII. 2.)

XCIII.

A Natural Group is steadily fixed, though not precisely limited; it is given in position, though not circumscribed ; it is determined, not by a boundary without, but by a central point within;—not by what it strictly excludes, but by what it eminently includes;—by a Type, not by a Definition, (VIII. 2.)

XCIV.

The prevalence of Mathematics as an element of education has made us think Definition the philosophical mode of fixing the meaning of a word: if (Scientific) Natural History were introduced into education, men might become familiar with the fixation of the signifi[462]cation of words by Types; and this process agrees more nearly with the common processes by which words acquire their significations, (VIII. 2.)

XCV.

The attempts at Natural Classification are of three sorts ; according as they are made by the process of blind trial, of general comparison, or of subordination of characters. The process of Blind Trial professes to make its classes by attention to all the characters, but without proceeding methodically. The process of General Comparison professes to enumerate all the characters, and forms its classes by the majority. Neither of these methods can really be carried into effect. The method of Subordination of Characters considers some characters as more important than others; and this method gives more consistent results than the others. This method, however, does not depend upon the Idea of Likeness only, but introduces the Idea of Organization or Function, (VIII. 2.)

XCVI.

A Species is a collection of individuals which are descended from a common stock, or which resemble such a collection as much as these resemble each other: the resemblance being opposed to a definite difference. (VIII. 2.)

XCVII.

A Genus is a collection of species which resemble each other more than they resemble other species: the resemblance being opposed to a definite difference, (VIII.2.)

XCVIII.

The Nomenclature of a Classificatory Science is the collection of the names of the Species, Genera, and other divisions. The binary nomenclature, which denotes a species by the generic and specific name, is now commonly adopted in Natural History, (VIII. 2.)

[463]

XCIX.

The Diagnosis, or Scheme of the Characters, comes, in the order of philosophy, after the Classification. The characters do not make the classes, they only enable us to recognize them. The Diagnosis is an Artificial Key to a Natural System, (VIII. 2.)

C.

The basis of all Natural Systems of Classification is the Idea of Natural Affinity. The Principle which this Idea involves is this:—Natural arrangements, obtained from different sets of characters, must coincide with each other, (VIII. 4.)

Whewell, William. 1847. The Philosophy of the Inductive Sciences: Founded Upon Their History. 2nd ed. 2 vols. London: John W. Parker.