Deductive Logic Part 59

3. Examine the following arguments--

(1) If we have a dusty spring, there is always a good wheat harvest. We shall therefore have a poor harvest this year, for the spring has not been dusty.

(2) Virtues are either feelings, capacities, or states; and as they are neither feelings nor capacities, they must be states.

(3) Everything must be either just or unjust.

Justice is a thing, and is not unjust.

.'. Justice is just.

Similarly justice is holy.

But the virtues of knowledge, justice, courage, temperance, and holiness were declared to be different from one another.

.'. Justice is unholy and holiness unjust.

CHAPTER XXIX.

Formulate the following trains of reasoning, resolve them into their component parts, and point out any violations of the rules of syllogism which they may contain--

(1) No Church Inst.i.tutions are useful; for they teach religious matters, not business matters, which latter are useful, being profitable.

(2) Mr. Darwin long ago taught us that the clover crop is dependent on the number of maiden ladies in the district. For the ladies keep cats, and the cats destroy the field-mice, which prey on the bees, which, in their turn, are all-important agents in the fertilisation of the clover flowers.

(3) Athletic games are duties; for whatever is necessary to health is a duty, and exercise is necessary to health, and these games are exercise.

(4) The iron-trade leads to the improvement of a new country; for furnaces require to be fed with fuel, which causes land to be cleared.

(5) 'Is stone a body?' 'Yes.' 'Well, is not an animal a body?'

'Yes,' 'And are you an animal?' 'It seems so.' 'Then you are a stone, being an animal.'

(6) If A is B, C is D.

If E is F, G is H.

But if A is B, E is F.

.'. If C is D, G is sometimes H.

(7) The soul is not matter.

My arm is not myself.

(8) Honesty deserves reward and a negro is a fellow-creature. Therefore an honest negro is a fellow-creature deserving of reward.

CHAPTER x.x.x.

1. Point out any ambiguities which underlie the following propositions--

(1) Every one who has read the book in French will recommend those who have not to read it in English.

(2) I will not do this because he did it.

(3) These are all my books.

(4) By an old statute of the date of Edward III it was accorded 'that Parliament should be holden every year once or more often if need be.'

(5) They found Mary and Joseph and the babe lying in a manger.

(6) The king and his minister are feeble and unscrupulous.

(7) Heres meus uxori meae triginta pondo vasorum argenteorum dato, quae volet.

2. Examine the following arguments, formulating them when sound, and referring them, when unsound, to the proper head of fallacy--

(1) We know that thou art a teacher come from G.o.d; for no man can do these signs that thou doest, except G.o.d be with him. S. John iii. 2.

(2) 'Sir Walter Scott's novels have ceased to be popular.' 'Well, that's only because n.o.body reads them.'

(3) What we produce is property.

The sheriff produces a prisoner.

.'. A prisoner is property.

(4) As all metals are not necessarily solid, we may expect some metals to be liquid.

(5) Moses was the son of Pharaoh's daughter.

.'. Moses was the daughter of Pharaoh's son.

(6) If Aeschines took part in the public rejoicings over the success of my policy, he is inconsistent in condemning it now; if he did not, he was a traitor then.

(7) It is wrong to stick knives into people.

.'. Surgeons ought to be punished.

(8) If a thing admits of being taught, there must be both teachers and learners of it.

.'. If there are neither teachers nor learners of a thing, that thing does not admit of being taught.

(9) It is unnecessary to lend books, if they are common, and wrong to lend them, if they are rare. Therefore books should not be lent from public libraries.

(10) Seeing is believing.

.'. What is not seen cannot be believed.

(11) St. Paul was not of Jewish blood, for he was a Roman citizen.

(12) To call you an animal is to speak the truth.

To call you an a.s.s is to call you an animal.

.'. To call you an a.s.s is to speak the truth.

(13) Pain chastens folly. A life of ease must therefore be one of folly incurable.

(14) We cannot be happy in this world; for we must either indulge our pa.s.sions or combat them.

(15) It must be clear to the most unlettered mind that, as all things were originally created by the Deity, including the hair on our heads and the beards on our faces, there can be no such thing as property.

(16) The crime was committed by the criminal.