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applicable to birds as well as to insects; in another sense, it would be too narrow, because there are many insects that only creep. But "wine" may be defined "the juice of the grape; because this can be affirmed of no other substance, and yet it applies to all proper kinds of wine. When a definition is thus adequate, it is reciprocal with the thing defined, and they may be mutually affirmed of, or substituted for, each other. Thus we may say, "the juice of the grape is wine," or "wine is the juice of the grape."

2. A definition must be clearer than the thing defined. It must be expressed in language as plain and simple as the subject will allow. It may happen, indeed, that the term defined is to some persons more familiar than the definition given; but nothing doubtful or difficult should be admitted into a definition, so that it may be generally and easily understood.

3. It should be expressed in as few appropriate words as possible. Too great brevity is not to be sought after, because, in this case, the subject may not be pointed out with sufficient definiteness; on the other hand, prolixity must be guarded against, as this would confuse the mind. Doubtful and equivocal, obscure and synonymous terms ought also, for the same reason, to be avoided. In a perfect definition we should not indulge in figurative and metaphorical language, as this might lead to indistinctness and ambiguity. But in an imperfect definition, or description, figurative language may be very properly introduced.

PART II.

OF JUDGMENT.

THE second mental operation employed in reasoning is Judgment, which is the comparing in the mind any two ideas, whether complex or incomplex, and pronouncing whether they agree or disagree. Judgment is that exercise of the mind by which we carry on this process; and when the decision which is thus formed is expressed in words it is called an enunciation, or a proposition. Under this head, then, Logic treats of the doctrine of Propositions.

CHAPTER I.

OF PROPOSITIONS.

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A PROPOSITION is an act of judgment expressed in words, and is defined logically a sentence indicative," that is, a sentence either affirming or denying; "sentence" is the genus, and "indicative the difference. No sentence is a proposition which does not either affirm or deny. For example, "Are you going to college?" is a question ;-" Let them go to college," is a permission, request, or command ; and, "Would that I were at college!" is an exclamation ; but none of these is a proposition, because nothing is affirmed or denied in any of these sentences. But, They are gone to

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college," and, "They are not gone to college," are each a proposition; because the one contains an affirmation, the other a denial.

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The above definition expresses the two parts of a proposition which cannot be separated from each other except in the mind. But it may be, perhaps, more clearly pointed out by mentioning its real parts which are actually separable. A proposition consists, then, of a subject, a predicate, and a copula. The subject is that respecting which anything is affirmed or denied; the predicate is that which is affirmed or denied of the subject; and the copula is some part of the substantive verb "to be," expressed or understood, connecting the subject and the predicate together. Thus, "Life is short," is a proposition, in which "life" is the subject; "short," the predicate; and "is," the copula. It is not necessary, however, that each of these terms should be separately expressed; the same proposition may, in some languages, be expressed by one, two, or three terms; thus, "vivo," "Ego vivo," or Ego sum vivens," all express the same proposition. "The mind thinks," is a complete proposition, although the copula be not expressed, for it is equivalent to "the mind is thinking:" "I live," signifies "I am living :" "Troy was," means Troy was existing :" "I am," that is, "I am living." In all these cases the subject, predicate, and copula are contained in the proposition, and are easily found out by expressing the proposition at length, and by asking the questions, "What am I speaking of?" and, "What am I saying respecting it?" In general, when the proposition is fully expressed, the subject stands first, and the predicate last, in a sentence; but this is not necessary; nor are they to be distinguished from each other by the place they occupy in the sentence, but by carefully marking the import of the expressions, and the design of the speaker. Thus, in the proposition, "Great is Diana of the Ephesians," the predicate "Great" stands first, and the subject, "Diana of the Ephesians," comes last in the sentence. "It is proper to study Logic;" here the subject stands last, and the predicate first; as may be seen by expressing the proposition in the more usual way; thus, "To study Logic is proper." The properties of these propositions merit particular attention. We shall first consider the Classes into which

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they have been arranged, and then notice their important Affections or relations.

CHAPTER II.

OF THE CLASSES OF PROPOSITIONS.

1. PROPOSITIONS, considered as sentences, are either categorical or hypothetical. A proposition may be expressed either absolutely, or under a hypothesis; and on this distinction the above division is founded. Thus, "Cæsar deserved death;" "Crassus was rich;" "Solomon was wise:" all these are categorical propositions, because they express the truth they contain in an absolute unconditional form. But, "If Cæsar was a tyrant, he deserved death;" "If Crassus was rich, his temptations to pride were numerous ;" "If Solomon was wise, his instructions should be regarded:" these are hypothetical propositions, because they are expressed in a conditional form, or in a hypothesis.

2. Propositions, with regard to their form, are either pure or modal. When a proposition asserts simply or purely that the subject does or does not agree with the predicate, it is called a pure proposition. But when it includes also the mode or manner in which the predicate is connected with the subject, it is called a modal proposition. Thus, "Brutus killed Cæsar," is a pure proposition; but, "Brutus killed Cæsar justly," is modal. "Intemperance will induce disease," is pure; "Intemperance will probably induce disease," is modal.

3. With regard to their matter, propositions must either be true or false. When the terms in which it is expressed agree with the thing signified, the proposition is true; when they do not agree, it is false. Hence a proposition must not be ambiguous, for in that case it has more than one meaning, and is in reality not one proposition but several; nor must it be imperfect or ungrammatical, for such an expression has no meaning at all. When a proposition is properly expressed, it is impossible it can be both true and false at the same time,

and in the same sense; yet two propositions, though both true, may seem to contradict one another, when used in different senses, or in different respects. Thus, man may be said to be both "mortal" and "immortal;" applying the one to his body, the other to his soul. Many seeming contradictions may be in this way explained.

4. With regard to their quality, propositions must either be affirmative or negative. They are affirmative when the predicate is said to agree with the subject; thus, "Man is an animal." They are negative when the predicate and subject do not agree; thus, "Man is not a tree." An affirmative proposition may be known by its copula being affirmative; thus, "Man is mortal;" ""Not to advance is to retrograde;" a negative proposition, on the contrary, is one whose copula is negative; as, "Man is not perfect;" "No man is innocent;" or, "Man is not innocent."

5. In respect of quantity, propositions are either universal or particular. When the predicate is affirmed or denied of the whole of the subject, the proposition is universal: when it is affirmed or denied only of a part of it, it is particular; thus, "All circles are figures;" "Ireland is an island ;” “No tyrant is happy," are universal propositions; and their subjects are said to be distributed, that is, each of them is understood to stand for the whole of its significates: but, "Some figures are squares ;" Some islands are fertile ;" "All men are not just," are particular propositions; their subjects are not distributed, being understood to stand only for a part of their significates. Universal propositions are generally denoted by the words, "all,” “ none," every;" and particular propositions by "some," "many," 99 66 a few," and so on.

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6. When the subject of a proposition is a common term, without any of the universal or particular signs expressed with it, the proposition is called indefinite; and the quantity of the proposition must be ascertained by the matter of it, or in other words, by the nature of the connexion between the extremes. This may be either necessary, or impossible, or contingent. If the matter of an indefinite proposition be necessary or impossible, the proposition is understood as a universal; thus, "Birds have wings," that is, "All birds have wings:" in this case the connexion between the extremes is necessary.

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