CHAPTER VI.

OF ABSTRACTION.

150. ABSTRACTION is the faculty by which we analyse the actual assemblages of nature into their constituent parts. It is this faculty which enables us to ascertain what qualities an object has peculiar to itself, and what are in common to it, and other objects of a like nature, which will therefore be referred to the same class with it. In short, the whole process of the formation of general notions is due to the faculty of abstraction alone.

Obs. Had we possessed no such faculty as abstraction, all our knowledge would have been limited to an acquaintance with individual beings and individual facts. But the very essence of science consists in generalizing and reducing to a few classes, or general principles, the multitude of individual things which every branch of human knowledge embraces. Hence, without abstraction, science would have had no existence; and the knowledge of man would have been like that of the lower animals, in whom no traces of this faculty are discernible; circumscribed to an acquaintance with those objects and events in nature with which he was connected by a regard to his own knowledge and preservation.

151. It is in the discovery of general principles, that reason has its noblest exercise. It is generalization alone that makes it possible for us continually to go on in scientific improvement.

Obs. It is in consequence of this, that at the moment when a multitude of particular solutions and of insulated facts begin to distract the attention, and to overcharge the memory, the former gradually lose themselves in one general method, and the latter unite in one general law; and that these generalizations continually succeeding one to another, like the successive multiplications of a number into itself, have no other limit than that infinity which the human faculties are unable to comprehend. Hence it appears, that abstraction is completely subservient to all the nobler exertions of reason; to those, in particular, by which man has attained the high distinction of being denominated a rational animal.

152. In proportion as a man familiarizes himself in the exercise of abstraction, and accustoms himself to consider what are the distinguishing characteristics of the various objects of his contemplation, and what they have in common with others, does he fit himself for scientific pursuits. Obs. But it has been supposed that the formation of general prin

ciples is not entirely suited to the direction of our conduct in the more ordinary occurrences of life; and hence the origin of that maxim which has been so industriously propagated by the dunces of every age-that a man of genius is unfit for business! But when theoretical knowledge and practical skill are happily combined in the same person, the intellectual power of man appears in its full perfection, and fits him equally to conduct with a masterly hand the duties of ordinary business, and to contend successfully with the untried difficulties of new and hazardous situations.

I. Of Abstract or general Terms.

153. The words we use in language are either general words, or proper names. Proper names belong to individuals, as George, London, Thames; common names, or general words, are not appropriated to signify any one individual thing, but are equally related to many; as man, horse, star.

Obs. Under general words are comprehended not only those which the logicians call general terms: that is to say, such words as may make the subject or the predicate of a proposition, but likewise their auxiliaries or accessories, such as prepositions, conjunctions, articles, which are all general words, though they cannot properly be called general terms.

154. In every language, rudé or polished, general words make the greatest part, and proper names the least. Grammarians have reduced all words to eight or nine classes, which are called parts of speech.

All verbs,

Illus. Proper names are found only among nouns. participles, pronouns, conjunctions, interjections and articles, are general terms. Of nouns all adjectives are general, and the greater part of substantives. Every substantive that has a plural number, is a general word; for no proper name can have a plural number, because it signifies only one individual. Custom, however, hath made a few proper names plural, but the position we have laid down is not overthrown by an exception. In all the books of Euclid's Elements, there is not one word that is not general.

Obs. At the same time, we observe, that all the objects which we perceive are individuals. Every object of sense, of memory, or of consciousness, is an individual. All the good things we desire or enjoy, and all the evils we feel or fear, must come from individuals.

155. The reason why proper names make but a very small and inconsiderable part of a language, is, that these names are local, and having no names answering to them in other languages, are not accounted a part of the language, any more than the customs of a hamlet are accounted part of the law of the nation, much less of the whole human family. For this reason there are but few proper names belonging to a language.

156. And the reason why general words make the greatest part of every language, may be easily accounted for by the following illustrations.

Illus. 1. Every individual that falls within our view has various attributes; and it is by these that it becomes useful or hurtful to us. We know not the essence of any individual object. All the knowledge we can gain of it is the knowledge of its attributes, its quantity, its various relations to other things, its place, its situation, its motions. It is by such attributes of things only that we communicate our knowledge of them to others. By their attributes, our hopes and fears from them are regulated: and it is only by attention to their attributes that we can make them subservient to our ends; and therefore we give names to such attributes.

2. Now all attributes must, from their nature, be expressed by general words, and are so expressed in all languages. Anciently attributes were, in general, expressed by two names which express their nature. They were called universals, because they might belong equally to many individuals, and are not confined to one. They were also called predicables, because whatever is predicated, that is, affirmed or denied of one subject, may be affirmed or denied of more than one, and is, therefore, an universal, and expressed by a general word. A predicable, therefore, signifies the same thing as an attribute, with this difference only, that the first word is Latin, the last English. The attributes which we find either in the works of nature, or of human ingenuity, are common to many individuals. We either find them to be so, or presume them to be so, and give them the same name in every subject to which they belong.

3. There are not only attributes belonging to individual subjects, but there are likewise attributes of attributes, which may be called secondary attributes. Most attributes are capable of different degrees and different modifications, which must be expressed by general words.

Example. Thus, it is an attribute of many bodies to be moved, but motion may be in an endless variety of directions. It may be quick, or slow, rectilineal or curvilineal; it may be equable, accelerated, or retarded.

Corol. As all attributes, therefore, whether primary or secondary, are expressed by general words, it follows, that in every proposition which we express in language, what is affirmed or denied of the subject of the proposition, must be expressed by general words. And that the subject of the proposition may often be a general word, will appear from the next illustration.

Illus. 4. The same faculties by which we distinguish the different attributes belonging to the same subject, and give names to them, enable us likewise to observe, that many subjects agree in certain attributes, while they differ in others. By this means we are enabled to reduce individuals which are infinite, to a limited number of classes, which are all kinds or sorts, and, in the scholas tic dialect, these are called general species.

157. Observing many individuals to agree in certain attributes, we refer them all to one class, and give a name to the class. This name comprehends in its signification, not one attribute only, but all the attributes which distinguish that class, and by affirming this name of any individual, we affirm it to have all the attributes which characterize the class.

Illus. Thus, men, dogs, horses, elephants, are so many different classes of animals. In like manner we marshal other substances, vegetable and inanimate, into classes; as, oaks, elms, firs; earths, minerals. We form also into classes, qualities, relations, actions, affections, and passions, and all other things.

158. When a class is very large, it is divided into subordinate classes; the higher class being called a genus or kind; the lower a species, or sort of the higher. Sometimes a species is still subdivided into subordinate species; and this subdivision is carried on as far as is found convenient for the purpose of language, or for the improvement of knowledge.

Illus. In this distribution of things into genera and species, it is evident that the name of the species comprehends more attributes than the name of the genus. The species comprehends all that is in the genus, and those attributes likewise which distinguish that species from others belonging to the same genus; and the more such divisions we make, the names of the lower become still the more comprehensive in their signification, but the less extensive in their application to individuals.

Corol. Hence it is an axiom in logic, that the more extensive any general term is, it is the less comprehensive; and on the contrary, the more comprehensive, the less extensive.

Example. In the following series of subordinate general terms, animal, man, Frenchman, Parisian, every subsequent term comprehends in its signification, all that is in the preceding, and something more; and every antecedent term extends to more individuals than the subsequent.

159. Every genus, and every species of things, may be either the subject or the predicate of a proposition, nay of innumerable propositions; for every attribute common to the genus or species, may be affirmed of it; and the genus may be affirmed of every species, and both genus and species of every individual to which it extends.

Illus. 1. Thus, of man, it may be affirmed, that he is an animal made up of body and mind; that he is of few days and full of trouble; that he is capable of various improvements in arts, in knowledge, and in virtue. In a word, every thing common to the species may be affirmed of man; and of all such propositions, which are innumerable, man is the subject.

2. Again, of every nation and tribe, and of every individual of the human race that is, that was, or that shall be, it may be affirmed that they are men. In all such propositions, which are innumerable, man is the predicate of the proposition.

Obs. We have observed above an extension and comprehension of general terms; and that in any subdivision of things, the name of the lowest species is most comprehensive, and that of the highest genus most extensive; we shall now see that, by means of such general terms, there is also an extension and comprehension of propositions which is one of the noblest powers of language, and fits it for expressing, with great ease and expedition, the highest attainments in knowledge of which the human understanding is capable.

160. When the predicate is a genus or a species, the proposition is more or less comprehensive, according as the predicate is so.

Illus. Thus, when I say, that this seal is gold, by this single proposition I affirm of it all the properties which that metal is known to have. When I say of any man, that he is a mathematician, this appellation comprehends all the attributes that belong to him as an animal, as a man, and as one who has studied mathematics. When I say, that the orbit of the planet Mercury is an ellipse, I thereby affirm of that orbit all the properties which Apollonius or other geometricians have discovered, or which may be discovered, of that species of figure.

161. Again, when the subject of a proposition is a genus or a species, the proposition is more or less extensive, according as the subject is.

Illus. Thus, when I am taught, that the three angles of a plane triangle are equal to two right angles; this proposition extends to every species of plane triangle, and to every individual plane triangle which has existed, which does exist, or which can exist.

Obs. Such extensive and comprehensive propositions condense human knowledge, and adapt it to the capacity of our minds with great addition to its beauty, and without any diminution to its distinctness and perspicuity.

II. Of General Conceptions.

162. Words could have no general signification, unless there had been conceptions in the minds of those who used them, of things that are general; and it is to such that we give the names of general conceptions. These conceptions take this denomination, not from the act of the mind in conceiving, which is an individual act, but from the object or thing conceived, which is general.

163. General conceptions are expressed by general terms, that is, by such general words as may be the subject or the predicate of a proposition; and these terms are ei