necessity or use, and to make it ambiguous where it was not. The distinctions in the end of categories of the four words, prius, simul, motus, and habere, are all verbal. The modes or species of prius, according to Aristotle, are five. One thing may be prior to another; first, in point of time; secondly, in point of dignity; thirdly, in point of order; and so forth. The modes of simul are only three. It seems this word was not used in the Greek with so great latitude as the other, although they are relative terms. The modes or species of motion he makes to be six, to wit, generation, corruption, increase, decrease, alteration, and change of place. The modes or species of having are eight. 1. Having a quality or habit, as having wisdom. 2. Having quantity or magnitude. 3. Having things adjacent, as having a sword. 4. Having things as parts, as having hands or feet.. 5. Having in a part or on a part, as having a ring on one's finger. 6. Containing, as a cask is said to have wine. 7. Possessing, as having lands or houses. 8. Having a wife. Another distinction of this kind is Aristotle's distinction of causes; of which he makes four kinds, efficient, material, formal, and final. These distinctions may deserve a place in a dictionary of the Greek language; but in English or Latin they adulterate the language. Yet so fond were the schoolmen of distinctions of this kind, that they added to Aristotle's enumeration, an impulsive cause, an exemplary cause, and I do not know how many more. We seem to have adopted into English a final cause; but it is merely a term of art, borrowed from the Peripatetic philosophy, without necessity or use; for the English word end is as good as final cause, though not so long nor so learned. SECTION IV. ON DEFINITIONS. IT remains that we make some remarks on Aristotle's definitions, which have exposed him to much censure and ridicule. Yet I think it must be allowed, that in things which need definition, and admit of it, his definitions are commonly judicious and accurate; and had he attempted to define such things only, his enemies had wanted great matter of triumph. I believe it may likewise be said in his favour, that until Locke's essay was written, there was nothing of importance delivered by philosophers with regard to definition, beyond what Aristotle has said upon that subject. He considers a definition as a speech declaring what a thing is. Every thing essential to the thing defined, and nothing more, must be contained in the definition. Now the essence of a thing consists of these two parts: first, what is common to it with other things of the same kind; and, secondly, what distinguishes it from other things of the same kind. The first is called the genus of the thing, the second its specific difference. The definition therefore consists of these two parts. And for finding them, we must have recourse to the ten categories; in one or other of which every thing in nature is to be found. Each category is a genus, and is divided into so many species, which are distinguished by their specific differences. Each of these species is again subdivided into so many species, with regard to which it is a genus. This division and subdivision continues until we come to the lowest species, which can only be divided into individuals, distinguished from one another, not by any specific difference, but by accidental differences of time, place, and other circumstances. The category itself being the highest genus, is in no respect a species, and the lowest species is in no respect a genus; but every intermediate order is a genus compared with those that are below it, and a species compared with those above it. To find the definition of any thing, therefore, you must take the genus which is immediately above its place in the category, and the specific difference, by which it is distinguished from other species of the same genus. These two make a perfect definition. This I take to be the substance of Aristotle's system; and probably the system of the Pythagorean school before Aristotle, concerning definition. But notwithstanding the specious appearance of this system, it has its defects. Not to repeat what was before said, of the imperfection of the division of things into ten categories, the subdivisions of each category are no less imperfect. Aristotle has given some subdivisions of a few of them; and as far as he goes, his followers pretty unanimously take the same road. But when they attempt to go farther, they take very different roads. It is evident, that if the series of each category could be completed, and the division of things into categories could be made perfect, still the highest genus in each category could not be defined, because it is not a species; nor could individuals be defined, because they have no specific difference. There are also many species of things, whose specific difference cannot be expressed in language, even when it is evident to sense, or to the understanding. Thus, green, red, and blue, are very distinct species of colour; but who can express in words wherein green differs from red or blue? Without borrowing light from the ancient system, we may perceive, that every definition must consist of words that need no definition; and that to define the common words of a language that have no ambiguity, is trifling, if it could be done; the only use of a definition being to give a clear and adequate conception of the meaning of a word. The logicians indeed distinguish between the definition of a word, and the definition of a thing; considering the former as the mean office of a lexicographer, but the last as the grand work of a philosopher. But what they have said about the definition of a thing, if it has a meaning, is beyond my comprehension. All the rules of definition agree to the definition of a word and if they mean by the definition of a thing, the giving an adequate conception of the nature and essence of any thing that exists; this is impossible, and is the vain boast of men unconscious of the weakness of human understanding. The works of God are all imperfectly known by us. We see their outside, or perhaps we discover some of their qualities and relations, by observation and experiment, assisted by reasoning; but we can give no definition of the meanest of them which comprehends its real essence. It is justly observed by Locke, that nominal essences only, which are the creatures of our own minds, are perfectly comprehended by us, or can be properly defined; and even of these there are many too simple in their nature to admit of definition. When we cannot give precision to our notions by a definition, we must endeavour to do it by attentive reflection upon them, by observing minutely their agreements and differences, and especially by a right understanding of the powers of our own minds by which such notions are formed. The principles laid down by Locke with regard to definition, and with regard to the abuse of words, carry conviction along with them; and I take them to be one of the most important improvements made in logic since the days of Aristotle; not so much because they enlarge our knowledge, as because they make us sensible of our ignorance, and show that a great part of what speculative men have admired as profound philosophy, is only a darkening of knowledge by words without understanding. If Aristotle had understood those principles, many of his definitions, which furnish matter of triumph to his enemies, had never seen the light: let us impute them to the times rather than to the man. The sublime Plato, it is said, thought it necessary to have the definition of a man, and could find none better than Animal implume bipes; upon which Diogenes sent to his school a cock with his feathers plucked off, desiring to know whether it was a man or not. SECTION V. ON THE STRUCTURE OF SPEECH. THE few hints contained in the beginning of the book concerning Interpretation, relating to the structure of speech, have been left out on treatises of logic, as belonging rather to grammar; yet I apprehend this is a rich field of philosophical speculation. Language being the express image of human thought, the analysis of the one must correspond to that of the other. Nouns adjective and substantive, verbs active and passive, with their various moods, tenses, and persons, must be expressive of a like variety in the modes of thought. Things which are distinguished in all languages, such as substance and quality, action and passion, cause and effect, must be distinguished by the natural powers of the human mind. The philosophy of grammar, and that of the human understanding, are more nearly allied than is commonly imagined. The structure of language was pursued to a considerable .extent, by the ancient commentators upon this book of Aristotle. Their speculations upon this subject, which are neither the least ingenious nor the least useful part of the Peripatetic philosophy, were neglected for many ages, and lay buried in ancient manuscripts, or in books little known, till they were lately brought to light by the learned Mr. Harris in his Hermes. The definitions given by Aristotle, of a noun, of a verb, and of a speech, will hardly bear examination. It is easy in practice to distinguish the various parts of speech; but very difficult, if at all possible, to give accurate definitions of them. He observes justly, that besides that kind of speech called a proposition, which is always either true or false, there are other kinds which are neither true nor false; such as, a prayer, or wish; to which we may add, a question, a command, a promise, a contract, and many others. These Aristotle pronounces to have nothing to do with his subject, and remits them to oratory, or poetry; and so they have remained banished from the regions of philosophy to this day: yet I apprehend, that an analysis of such speeches, and of the operations of mind which they express, would be of real use, and perhaps would discover how imperfect an enumeration the logicians have given of the powers of human understanding when they reduce them to simple apprehension, judgment, and reasoning. SECTION VI. ON PROPOSITIONS. MATHEMATICIANS use the word proposition in a larger sense than logicians. A problem is called a proposition in mathematics, but in logic it is not a proposition: it is one of those speeches which are not enunciative, and which Aristotle remits to oratory or poetry. A proposition, according to Aristotle, is a speech wherein one thing is affirmed or denied of another. Hence it is easy to distinguish the thing affirmed or denied, which is called the predicate, from the thing of which it is affirmed or denied, which is called the subject; and these two are called the terms of the proposition. Hence likewise it appears, that propositions are either affirmative or negative; and this is called their quality. All affirmative propositions have the same quality, so likewise have all the negative; but an affirmative and a negative are contrary in their quality. When the subject of a proposition is a general term, the predicate is affirmed or denied, either of the whole, or of a part. Hence propositions are distinguished into universal and particular. All men are mortal, is an universal proposition; Some men are learned, is a particular, and this is called the quantity of the proposition. All universal propositions agree in quantity, as also all particular: while an universal and a particular are said to differ in quantity. A proposition is called indefinite, when there is no mark either of universality or particularity annexed to the subject: thus, Man is of few days, is an indefinite proposition; but it must be understood either as universal or as particular, and therefore is not a third species, but by interpretation is brought under one of the other two. There are also singular propositions, which have not a general term but an individual for their subject; as, Alexander was a great conqueror. These are considered by logicians as universal, because, the subject being indivisible, the predicate is affirmed or denied of the whole, and not of a part only. Thus all propositions, with regard to quality, are either affirmative or negative; and with regard to quantity, are universal or particular; and taking in both quantity and quality, they are universal affirmatives, or universal negatives, or particular affirmatives, or particular negatives. These four kinds, after the days of Aristotle, came to be named by the names of the four first vowels, A, E, I, O, according to the following distich: Asserit A, negat E, sed universaliter ambæ ; |