Chapter 6 Lecture Notes Working on Relevance

Chapter 6 Understanding Relevance: The second condition for cogency for an argument is the (R) condition and we are going to look at the three basic ideas of relevance. (i)Positive relevance (ii)Negative relevance (iii)Irrelevance

Chapter 6 Positive Relevance: Statement A is positively relevant to statement B if and only if the truth of A counts in favor of the truth of B. Premises are positively relevant to their conclusion when, if true, they provide some reason to believe that the conclusion is true. When there is positive relevance, one statement supports another.

Positive Relevance: An Example Statement A: Students who eat regularly at the college cafeteria have higher incidences of intestinal distress than students who do not. Statement B: Food prepared at the college cafeteria is harmful to student health.

Chapter 6 Negative Relevance: Statement A is negatively relevant to statement B if and only if the truth of A counts against the truth of B. Premises are negatively relevant to their conclusion when, if true, they provide some reason to think that the conclusion is false. When there is negative relevance, one statement undermines another. Negatively relevant premises constitute counterconsiderations or objections to their conclusion.

Negative Relevance: An Example Statement A: Students who eat regularly at the college cafeteria have lower levels of cholesterol and saturated fat in their diet than students who do not. Statement B: Food prepared at the college cafeteria is harmful to student health.

Chapter 6 Irrelevance: Statement A is irrelevant to statement B if and only if the truth of A counts neither for nor against the truth of B. A doesn’t provide a reason to or a reason not to believe in the truth or falsity of B. When there is irrelevance, there is no relation of logical support or logical undermining between the two statements.

Irrelevance: An Example Statement A: Students at York College enjoy their critical thinking classes very much. Statement B: Food prepared at the college cafeteria is harmful to student health.

Chapter 6 The failure of premises to be positively relevant to the conclusion constitutes a serious flaw in an argument. An argument in which the premise or premises are irrelevant is sometimes called a non sequitur. Non sequitur is Latin for “it does not follow.” Another term used for irrelevance is red herring. A red herring is a distracting remark that is irrelevant to the argument at issue.

Ways of Being Relevant Argument patterns in which the premises are linked: Deductive Entailment: When the premises taken together deductively entail the conclusion, they are relevant to the conclusion. The premises give full logical support to the conclusion. All human beings are mortal. Socrates is a human being. Therefore, Socrates is mortal. All human beings are mortal. Socrates could really hold his liquor. Therefore, Socrates is mortal.

Inductive Generalizations: Past events or experiences are relevant to future events or experiences because of the basic assumption that regularities that have been encountered in the past will persist. The experienced events are relevant to those not experienced, for the inductive assumption is basically reasonable. In Ireland, disputes between contending Protestant and Catholic groups led to the partitioning of the country into Northern and Southern Ireland, and there is still fighting in Ireland today. In India, disputes between Muslims and Hindus led to the partitioning of the country in India and Pakistan, and there is much ill will and some fighting between India and Pakistan. In Vietnam and Korea, similar divisions have led to continued fighting and tensions. It seems clear that partitioning countries that are experiencing religious or ideological conflict is a poor method of resolving conflicts within them.

Arguments from Analogy: One experience, case, or type is relevant to another experience, case, or type when they are similar. When we argue on the basis of analogy, the similarities between the two things compared make points about one relevant to our consideration of the other. Premises are irrelevant when the things being compared are in fact completely different. Simple appliances like toasters and washing machines break down. They are not completely reliable. The same companies that make these appliances make nuclear reactors, which are much more complicated. It is very likely, then, that nuclear reactors will also be susceptible to break- downs. In South Africa, blacks and whites are going to have to get along. South Africa is a lot like a zebra in that both are made up of black and white parts and if either part of a zebra is shot, the animal itself dies. We can see that neither blacks nor whites should engage in violence toward the other.

Argument patterns in which the premises are convergent: Conductive Arguments: When premises converge separately on a conclusion, the relevance of each premise has to be assessed separately. Each premise, independently of the others, should count in favor of the conclusion. In conductive arguments, it is not unusual to include negatively relevant premises, counterconsiderations. Consensus is the best approach to making decisions in small groups. For one thing, no view or person is overpowered by the majority. For another, the discussion and reflection required to reach a consensus help to establish understanding of the subject under discussion. Another positive factor is that the process of respectfully listening to others and considering their views cultivates good relationships between the people in the group. Even though working by consensus may be slow, it is worthwhile.