10TH MEETING

Analogy and Probable inference

Definition

Analogical argument is one of the most kind in the analysis of inductive argument

Analogy is relationship between one and others based on likeness and similarity or comparison

We draw an analogy when we indicate one or more respects in which two or more entities are similar.

An argument by Analogy

An argument by analogy is an argument in which the similarity of two or more respects is used as premise(es); its conclusion is that those entities are similar in some further respect.

Exercises

Distinguish the analogies that contain analogical arguments from those that make nonargmentative uses of analogy.

1. A Man ought no more to value himself for being wiser than a Woman, if he owes his Advatage to a better Education, than he ought to boast of his Courage for beating Man when his hands were bound (Mary astell, An Essay in defence of the Female Sex (1721), quoted in Germaine Greer, The Female Eunuch)

2. The brain secretes thought as the stomach secretes gastric juice, the liver bile, and the kidneys urine. (Karl Vogt, Koblerglaube and wissenschaft)3. .... It astonishes me that the exploitation of

women should be no readily accepted. When one thinks of the ancient democracies, deeply attached to the ideal of equality, it is difficult to see how they can possibly have thought the status of the slaves natural: anyone would suppose that the contradiction must have been glaringly obvious to them. Perhaps one day posterity will wonder with the same astonishment how the bourgeois or popular democracies of our day can conceively have maintained as basic inequality between the two sexes, and have maintained it without the lest qualm of conscience

4.Thinking is experiemental dealing with small quantities of energy, just as a general moves miniature figures over a map before setting his troop in action. (Sigmund Freud, New Introductory lectures on Psychoanalysi)5. One of the pleasures of science is to see two

distant and apparently unrelated pieces of information suddenly come together. In a flash what one knows doubles or triples in size. It is like working on the large but separate sections of a jigsaw puzzle and, almost without realizing it until the moment it happens, finding that they fit into one (John Tyler Bonnerm “Hormones in social Amoebae and Mammals” Scientific American, vol.221, November 1969)

The use of analogy

Not all analogies are used for purposes of explanation. They may also serve for literary effect, or for purposes of explanation.

Example of literary effect: A poem withe the title a letter to a friend, by Yumarma (June 25, 1982)

Because of analogical arguments are inductive, not deductive, not deductive, the term validity and invalidity do not apply to them.

The conclusion of analogical argument has some degree of probability but is not claimed to be certain.

6 criteriaThe number of entities between which the

analogy is said to holdThe number of respects in which the entities

involved are said to be analogousThe modesty (or boldness) of its conclusion

relative to its premisesThe number of dis-analogies between the

instances mentioned only in the premises and the instance mentioned in the conclusion

The degree of dissimilarity among the instances mentioned only in premises

The relevance of the respects mentioned in the premises to the respect mentioned in the conclusion

Refutation by logical analogy

An effective method of refuting arguments, both inductive and deductive. To show a given argument mistaken, it compelling to present another argument, obviously mistaken that is identical in form to the argument under attack.