JB_101_293.xml

Title: [19 Aug. 1814 Logic Ch. Division]

Description: 19 Aug. 1814

Logic

Ch. Division ?

Dichotomous why

6

19 Jan 1816. Examined these 2 pages with a view to Chrestom v. Nomenclature. Supposed not necessary to be employed.

Ch. ' Of Logical Division [...?]

In the case of a physical aggregate of the physical kind, it has /may have/ been seen, the greatest number of integral parts into which it is capable of being divided is always a determinate number: in a bushel of apples containing 400 apples, 400 is that number; in a bushel of wheat containing 400,000 grains of wheat, 400,000 is that number in a garden-full of plants 40,000 in number each of those of a different species, 40,000 is that number.

These 40,000 plants each of them of a species distinguishable from every other species suppose it required so to divide into subordinate and lesser aggregates the universal or all comprehensive aggregate designated by the /of which by the supposition the word plant is the/ name of plant - to divide it in such sort that by a series of successive divisions by /from/ the descriptions given of the products of these several divisions, {it} should be made to appear in what way /points/ each agreed /coincided/ with and in what points it disagreed with the description given of every other ? + In this case, /The following is/ the only mode of proceeding by which the object can be accomplished is the following. Divide the whole aggregate into two equal parts or say divisions: divide each of these divisions into others which call divisions of the 2d order, calling the two first mentioned divisions being second divisions of the 1st order: each of these divisions dividing always by two divide into divisions of the 3rd order: the total number of divisions eight; and go on dividing always by two until the whole number of the component aggregates thus formed comes to be 40,000,+ the assumed number of different species of plants. This mode of division is termed from the Greek dichotomous; from the Latin, bifurcate, two-forked.

+that instead some power of 2.

200

JB_101_304.xml

Title: [19 Aug. 1814 C Logic 1]

Description: 19 Aug. 1814 C

Logic

1

Ch. Division

'. Synthesis and Analysis

correspond not

7

An inference that presents itself as an obvious one, is - that in the instance of every such aggregate the number of integral parts contained in a logical aggregate being a limited, in a word, a given, a determinate, or, at any rate, a determinable number

{Such accordingly} it would be, were it not for the powers - the unlimited powers, of decomposition and recomposition possessed by the human mind, - of these powers, one effect is to exclude as fruitless every possible attempt at circumscribing within any limited extent the number of such parts into which a logical whole is capable of being divided.

In the case of physical aggregate, it may be done; but not so in the case of logical ones. Take a bushel of apples: the number of integrant parts of that aggregate, each apple constituting one of those integrant parts, will be the number of apples that were put into the bushel, neither more nor less. Some time /years/ ago, the aggregate number of all the species of plants then known was estimated at 40,000. Suppose a garden, and in it a specimen of every one of these 40,000 species; 40,000, neither more nor less, is, in this case, the exact number of integrant parts into which the aggregate here in question is capable of being divided. But, upon this supposition, 40,000 is not equal to the number of integrant parts call species, into which the logical aggregate, designated by the names of plant and vegetable, is capable of being divided.

211

JB_101_302.xml

Title: [21 Aug. 1814 Logic Ch. Division]

Description: 21 Aug. 1814

Logic

Ch. Division

'. Synthesis and Analysis

correspond not

5

Far indeed from being thus limited is the number of aggregates of different orders capable of being formed by the decomposition of that all-embracing aggregate.

Division the first all-comprehensive. - Divide the aggregate of universal amplitude being or substance into its two aggregates immediately issuing from it, you have corporeal beings and incorporeal. For corporeal beings, say, in one word, bodies; as, on the other hand, for incorporeal beings, in one word, spirits.

Division the Second. - Divide the aggregate, corporeal beings, into its proximate component aggregates, living and not- living; for its proximate component aggregates, you have those endued with life and those not endued with life, to which latter description belong mineral bodies.

Division the Third. - Divide the aggregate corporeal beings endued with life, into its proximate component aggregates, you have such as are endued with animal life, with sensation as well as life, say in one word animals; and such as are not endued with sensation as well as life, say in one word vegetables.

It was from the observation and contemplation of individual animals, and from the observation made of a quality which such of them as were most exposed to observation had in common with one another, and which was not observed or observable in vegetables, viz. the habitual act of respiration, that the common name, expressive of the faculty corresponding to the exercising of that act, viz. animal, was first formed. Here then are four stages which have place alike in the ascending and the descending line.

209