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(ii) The Complex Constructive Dilemma is of this form :

If a politician (who finds he is wrong) changes
his views, he is inconsistent; and if he does
not change them, he is not conscientious;
He must either change them or not change them;
Therefore he must be either inconsistent or not
conscientious.

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(iii) The Destructive Dilemma is of this form :— If a man were wise, he would not jest at Scripture in fun; and if he were good, he would not do so in earnest;

He must do it either in fun, or in earnest;

Therefore he must be either not wise or not good.

These three (the substance of which is borrowed from Mr. Jevons's book) will be quite enough to show that you understand what dilemma means. A dilemma may be rebutted thus: 1st Dilemma. "Do not enter into public affairs; for if you say what is just, men will hate you; and if you say what is unjust, the gods will hate you. You must do one or the other; therefore you must be hated by gods or by men." 2nd Dilemma. "Do enter into public affairs; for if you say what is unjust, men will love you; and if you say what is just, the gods will love you; therefore you must be loved by gods or men.' "In the "Oxford Spectator" I saw a dilemma,' said I, which seemed conclusive. How would you

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rebut this: "Examinations are useless; for if you know the questions already, they teach you nothing; and if you do not know the questions, they teach you nothing; you must either know them or not know them; therefore examinations are useless ?",

To which Dyver replied, to my astonishment: • Examinations are useful; for if we do know the questions, they teach us how to express our knowledge; and if we do not know the questions, they teach us what our weak points are (and it is not their fault if we do not remedy them); we must either know the questions or not know them; therefore examinations must be useful.'

Mr. Practical expressed his approval, and I began to think that if Mr. Practical taught Dyver much more it would be a case of the young horse running away with the 'coach' altogether.

CHAPTER XXII.

PROBABLE REASONING.

‘HITHERTO We have spoken of syllogisms with strictly logical forms of propositions for their premisses, when the conclusions are certain. There are two kinds of reasoning which furnish us with conclusions not strictly certain, but of sufficient weight to influence our actions in life-self-infirmative, and selfconfirmative inference. By help of such probable reasoning we are enabled to make syllogisms out of propositions with the sign "most" or "many," instead of "all" or 66 some;" and we can take into account the force of such words as "probably," without (as in strict Logic) thrusting them into the subject or prædicate.

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(i.) Self-infirmative inference is where each fresh fact weakens the conclusion, so that the more premisses you have the less likely is it that the conclusion will be true. "Never go out of doors in a severe frost," says the anxious mother, "because the Humane Society's men are obliged to drink.”

'But what has that to do with my "going out?" you ask.

""You know," she replies, "some of those who go out in such times are tempted to skate, and some of those who skate break the ice, and some of those who break the ice are rescued by the Humane Society's men, and some of these men drink to keep themselves warm; therefore, some of the men who venture out in a severe frost may have to be rescued by possibly intoxicated men."

"You laugh at this argument, because every fresh premiss weakens the conclusion. So with the words

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possibly,"
," "probably," &c.

'By this process you can argue that men with money are likely to commit suicide; thus:

Men with money probably invest it;
Men who invest probably speculate;
Men who speculate possibly lose all;

Men who lose all are probably pinched with
poverty;

Men who are pinched with poverty probably
despair;

Men who despair possibly commit suicide.

.. To this extent men with money are likely to

commit suicide.

The amount of the probability may be estimated to a fraction; but calculations of this sort seem to belong rather to mathematics than Logic.'

'What a comfort!' I reflected.

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(ii.) Self-confirmative inference is where each fresh fact strengthens the conclusion you wish to

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establish. It is called "circumstantial evidence," or a "chain coil" of evidence. Many verdicts are awarded in the Law Courts solely upon the strength of this evidence, which amounts in some. cases almost to certainty. Each fact may be regarded as the minor premiss of a syllogism, with a probable major premiss and a probable conclusion. Given the assertion "That our cook gave the joint to a follower. when she said the dog ate it." It is required to prove this assertion by circumstantial evidence-for nobody actually saw her give it. The evidence is as follows:-"The dog was a remarkably well-behaved dog." "On the day of the mysterious disappearance the kitchen blinds were kept down." "Certain other articles (such as beer, tea, spirits, &c.), which dogs would not eat or drink, vanished during the same cookship," &c. Each of these facts becomes the premiss of a syllogism; thus:

I.

Well-behaved dogs probably are innocent of a theft.

This was a well-behaved dog.

.. The dog is probably innocent of the theft.

II.

The drawing of the blinds probably betokened the presence of a follower.

The blinds were drawn.

.. A follower was probably present.

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