A System Of Logic, Ratiocinative And Inductive

nation, Or

t work, which is not designed as a manual, it is sufficient to recapitulate, memori? causa, the leading results of that analysis

subject and predicate of the conclusion, and another called the middle term, which must be found in both premises, since it is by means of it that the other two terms are to be connected together. The predicate of the conclusion is called the major term of the syllogism; the subject of the conclusion is called the minor term. As ther

. The most common case is that in which [pg 127] the middle term is the subject of the major premise and the predicate of the minor. This is reckoned as the first figure. When the middle term is the predicate in both premises, the syllogism belongs to t

ng as they are universal or particular, affirmative or negative. The following are examples of all the legitimate moods, that

t Fi

B is C All B

A is B Some A i

refore theref

is C Some A is C

nd F

C is B No C

is B Some A is B

refore theref

C Some A is not

d Fi

me B is C All B is C So

All B is A Some B is A

therefore therefor

Some A is C Some A is C So

th F

is B Some C is B

A All B is A All

ore therefore th

ot C Some A is C Some A

cause such propositions are not used in ratiocination, but because, their predicate being affirmed or denied of the whole o

ortal, All me

e men, Socra

ore th

mortal, Socr

, and are both ranked in the fi

ersal and particular, affirmative and negative propositions), any person taking interest in these inquiries may be presumed to have either learned from the common-school books of the syllogistic logic, or to be capable of discovering for himself. The rea

propositions equally or less general are inferred; may be exhibited in some of the above forms. The whole of

the first figure alone. The rules for throwing an argument in any of the other figures into the first figure, are called rules for the reduction

C i

A

ref

A i

n, and may be changed into No B is C, which, as we showed, is the very same assertion in other words-the same

B i

A

ref

A i

e first figure. Again, an argument in the first mo

B

B

ref

A i

e converted per accidens, thus, Some A is B; which, though it does not express the whole of what is asserted in the proposition All B is A, expresses, as was formerly shown

B

A i

t obviously

A i

of the four moods of the first. In other words, every conclusion which can be proved in any of the last three figures, may be proved in the first figure from the same premises,

very B is

s B, Al

s B, Som

ore th

s C. No

C. Some

nificant symbol

he argument must admit of

mals ar

men/Socrate

ref

men/Socrate

gument must be capable of b

e of self-control is

e of self-control is

es/Mr. A's negro are c

ref

es are not/Mr. A's negro

sequence; there are, no doubt, cases in which the argument falls more naturally into one of the other three figures, and in which its conclusiveness is more apparent at the first glance in thos

es was

es was

ref

an was v

nd would carry conviction more instantly home, than the

es was

an was A

ref

an was v

ressed; since, as we have already seen, the premises of a syllogism in the second, third, or fourth figure, and those of the syllogism in the first figure to which it may be reduced, are the same premises in every thing except language, or, at least, as much of them as contributes to the proof of the conclusion is the same. We are therefore at liberty, in conformity with the general opinion of logicians, to consider the two elementary forms of the first figure as the universal types of

the conclusion is so too. All ratiocination, therefore, starts from a general proposition, principle, or assumption: a proposition in which a predicate is affirmed or denied of an entire class; that i

class respecting which something was affirmed or denied in the major premise. It follows that the attribute affirmed or denied of the entire class may (if that affirmat

erected into a logical maxim, on which all ratiocination is said to be founded, insomuch that to reason, and to apply the maxim, are supposed to be one and the same thing. The maxim is, That whatever can be aff

cal proposition, but a statement of what was conceived as a fundamental law of the universe. The assertion that the entire nature and properties of the substantia secunda formed part of the nature and properties of each of the individual substances called by the same name; that the properties of Man, for example, were properties of all men; was a proposition of real significance when man did not mean all men, but something inherent in men, and vastly superior to them in dignity. Now, however, when it is known that a class, a universal, a genus or species, is not an entity per se, but neither more nor less than the individual substances themselves which are placed in the class, and that there is nothing real in the matter except those objects, a common name given to them, and common attributes indicated by the name; what, I should be glad to know,

ring them as mere names, could not free themselves from the notion that the investigation of truth consisted entirely or partly in some kind of conjuration or juggle with those names. When a philosopher adopted fully the Nominalist view of the signification of general language, retaining along with it the dictum de omni as the foundation of all reasoning, two such premises fairly put together were likely, if he was a consistent thinker, to land him in rather startling conclusions. Accordingly it has been seriously held, by writers of deserved celebrity, that the process of arriving at new truths by reasoning consists in the mere substitution of one set of arbitrary signs for another; a doctrine which they suppose to derive irresistible confirmation from the example of algebra. If there were any process in sorcery or necromancy more preternatural than this, I should be much surprised. The culminating point of this philosophy is the noted aphorism of Condillac, that a science is nothing, or scarcely any thing, but une langue bien faite; in other words, that the one sufficient rule for discovering the nature and properties of objects is to name them properly: as if the reverse were not the truth, that it is impossible to name them properly except in proportion as we are already acqua

combination of propositions in a syllogism. If the minor premise asserted nothing more than that something belongs to a class, and if the major premise asserted nothing of that class except that it is included in another class, the conclusion would only be that what was included in the lower class is included in the higher, and the result, therefore, nothing except that the classification is consistent with itself. But we have seen that it is no sufficient account of the meaning of a proposition, to say that it refers something to, or excludes something from, a class. Every

t all things which have a certain attribute (or attributes) have or have not along with it, a certain other attribute (or attributes). The minor premise asserts that the thing or set o

n are

es is

ref

es is

s of attributes, we always find the other: that the attributes connoted by "man" never exist unless conjoined with the attribute called mortality. The assertion in the minor premise is t

All men a

ngs ar

ref

gs are

the word man. The major asserts as before, that the last-mentioned attributes are never found without the attribute

that they never exist with, those connoted by "omnipotent:" from which, together with the minor premise, it is concluded, that the same incompatibi

cs. The first, which is the principle of affirmative syllogisms, is, that things which co-exist with the same thing, co-exist with one another: or (still more precisely) a thing which co-exists with another thing, which other co-exists with a third thing, also co-exists with that third thing. The second is the principle of negative syllogisms, and is to

s a portion of our knowledge of nature, or as a memorandum for our guidance. Under the former, or speculative aspect, an affirmative general proposition is an assertion of a speculative truth, viz., that whatever has a certain attribute has a certain other attribute. Under the other aspect, it is to be regarded not as a part of

is a mark of

object has

ref

ject has the

ave lately cited as specimens of the syllogism,

n are a mark of the

s the attri

ref

the attribu

8] And

n are a mark of the

king are a mark of t

ref

ing are a mark of the

las

a mark of the absence of

king are a mark of t

ref

of the attribute signified by the word omnipotent (

hich it is a mark of. Or, when the minor premise as well as the major is universal, we may state it thus: Whatever is a mark of any mark, is a mark of that which this last is a mark of. To trace the identity of these axioms with those previously laid down, may be left to the intelligent reader. We shall

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