Let’s review what an inductiveargument is.Any argument whose premises may provide evidence forits conclusion or hypothesis but do not guarantee it.Here’s an example of an inductive argument: 1. Pam is athletic. 2. Most of those who are athletic don’t eat junk food. _____________________________________________________________________________________________________________ 3. Pam doesn’t eat junk food.
To determine whether an argumentis inductive, consider: • whether it would be possible for an argument with the same form to have true premises and a false conclusion • whether one can assert its premises and deny its conclusion without contradiction • whether the conclusion adds information not contained in the premises
Enumerative InductionAlways has a universal conclusion to the effectthat all things of a certain kind have (or lack) acertain feature. This conclusion is drawn fromevidence that some things of that kind have (orlack) that feature.The conclusion of this type of argument, oftencalled an inductive generalization, is a universalgeneralization.
Enumerative induction attempts to support universalgeneralizations by using non-universal generalizationsor specific statement as premises. 1. Many roses have been observed to blossom in the summer. _______________________________________________________________________________________________ 2. All roses blossom in the summer. --or-- 1. Rose 1 has been observed to blossom in the summer. 2. Rose 2 has been observed to blossom in the summer. 3. Rose 3 has been observed to blossom in the summer. . . 4. Rose number n, has been observed to blossom in the summer. __________________________________________________________________________________________________________ 5. All roses blossom in the summer.
So what’s a universal generalization?A statement asserting that all of the members of a certainclass have (or don’t have) a certain feature.May be expressed by a great number of different patternsof sentence. Some standard patterns: • “all . . . are” • “every . . . is” • “no . . . is”
Non-Universal GeneralizationA statement asserting that some, perhaps many, of themembers of a class have (or don’t have) a certainfeature.May be expressed by a great number of differentpatterns of sentence. Some standard patterns: • “most . . . are” • “a few . . . are” • “many . . . are” • “n percent of . . . are” (where n is less than 100%) • “some . . . are” • “some . . . are not”
Statistical SyllogismA statistical syllogism is an inductive argumentwhereby a certain feature is ascribed to a case orcases on the basis of their being subsumed withina larger class of things, some of which, perhapsmany, have the ascribed feature. 1. Most surgeons carry malpractice insurance. 2. Dr. Hagopian is a surgeon. ________________________________________________________________________________________________________________ 3. Dr. Hagopian carries malpractice insurance.
Causal ArgumentAccording to the textbook, a causal argumentmakes the claim that two or more things orevents are causally related in either of theseways: • Effect E results from cause C. • C causes E. • E and C are the cause or the effect of another thing X.
Examples of Causal Arguments• HIV causes AIDS.• Having the genome of a cat causes Fluffy the kitten to grow up to be a cat.
Three Meanings of Cause• Sufficient Cause: C is a sufficient cause of E if, and only if, C always produces E.• Necessary Cause: C is a necessary cause of E if, and only if, E cannot occur in the absence of C.• Necessary and Sufficient Cause: C is a necessary and sufficient cause of E if, and only if, C always is the sole cause of E.
AnalogyAnalogy is a type of inductive argument whereby acertain conclusion about individuals, qualities, orclasses is drawn on the basis of some similarities withother individuals, qualities, or classes.Whether an analogy succeeds depends on: • the number of things and the number of features held to be analogous • the degree of similarity or dissimilarity among those things • the relevance of ascribed features to the hypothesis • the boldness of the hypothesis with respect to the evidence
Here’s an example of an AnalogicalArgument:This is the argument’s form:
Criteria for Inductive ArgumentEvaluationReliability Concerns argument form and is, in this respect, comparable to validity for deductive arguments. In a reliable argument, the relation of premises to conclusion is such that, if all the premises were true, it would be reasonable to accept the conclusion.Strength Requires that the inductive argument be reliable and have true premises (compare deductive soundness). When an argument is inductively strong, it’s reasonable to accept its conclusion.
The “Cash Value” of Reliabilityand StrengthInductive Reliability’s Cash Value If an argument has a good share of reliability, then it would be reasonable to accept its conclusion, provided that its premises are true.Inductive Strength’s Cash Value If an argument has a good share of inductive strength, then it’s reasonable to accept its conclusion, since it has a reliable form and its premises are true.