Critical thinking final part 1

Induction​ ​Handout

1. Opposed​ ​to​ ​deduction,​ ​inductive​ ​arguments​ ​try​ ​to​ ​offer​ ​probabilistic​ ​support​ ​for​ ​a​ ​conclusion.​ ​At best,​ ​the​ ​conclusion​ ​follows​ ​in​ ​a​ ​highly​ ​likely​ ​way,​ ​making​ ​it​ ​irrational​ ​to​ ​think​ ​that​ ​the conclusion​ ​is​ ​unsupported​ ​or​ ​false,​ ​for​ ​example.​ ​Importantly,​ ​it​ ​is​ ​always​ ​possible​ ​that​ ​the conclusion​ ​is​ ​false,​ ​even​ ​for​ ​the​ ​best​ ​inductive​ ​argument.​ ​Given​ ​the​ ​premises,​ ​however,​ ​it​ ​is irrational​ ​to​ ​think​ ​that​ ​it​ ​is.​ ​Note​ ​the​ ​difference​ ​between​ ​possibility​ ​and​ ​probability​ ​and​ ​do​ ​not confuse​ ​the​ ​two.

2. Inductive​ ​arguments​ ​still​ ​need​ ​proper​ ​form​ ​and​ ​true​ ​premises​ ​to​ ​be​ ​good​ ​arguments.​ ​When​ ​an inductive​ ​argument​ ​has​ ​the​ ​form​ ​​if​ ​the​ ​premises​ ​are​ ​true​ ​the​ ​conclusion​ ​is​ ​​probably​​ ​true​,​ ​it​ ​is strong​;​ ​when​ ​it​ ​fails​ ​to​ ​have​ ​this​ ​form,​ ​it​ ​is​ ​​weak​;​ ​when​ ​it​ ​has​ ​both​ ​strong​ ​form​ ​and​ ​verified​ ​true premises​ ​it​ ​is​ ​​cogent​.​ ​Remember,​ ​induction​ ​infers​ ​by​ ​going​ ​beyond​ ​the​ ​evidence​ ​in​ ​concluding something;​ ​it​ ​is​ ​always​ ​a​ ​kind​ ​of​ ​leap​ ​between​ ​premise​ ​and​ ​conclusion.​ ​The​ ​question​ ​is​ ​if​ ​the​ ​leap beyond​ ​the​ ​evidence​ ​is​ ​supported​ ​by​ ​the​ ​evidence.

3. To​ ​identify​ ​an​ ​inductive​ ​argument,​ ​look​ ​for​ ​indicator​ ​language​ ​that​ ​implies​ ​probability​ ​as​ ​the tactic,​ ​words​ ​and​ ​phrases​ ​like​ ​the​ ​following:​ ​it​ ​is​ ​​probably​​ ​the​ ​case​ ​that,​ ​it​ ​is​ ​most​ ​​likely​​ ​true​ ​that, there’s​ ​​more​​ ​reason​ ​to​ ​believe​ ​that;​ ​look​ ​for​ ​concepts​ ​that​ ​imply​ ​but​ ​also​ ​limit.

4. In​ ​evaluating​ ​inductive​ ​arguments,​ ​ask,​ ​as​ ​always,​ ​what​ ​happens​ ​if​ ​the​ ​premises​ ​are​ ​true.​ ​If​ ​the premises​ ​are​ ​true,​ ​does​ ​the​ ​conclusion​ ​likely​ ​follow?​ ​Additionally,​ ​since​ ​induction​ ​is​ ​messier​ ​than deduction,​ ​ask​ ​if​ ​the​ ​premises​ ​are​ ​sufficient,​ ​or​ ​if​ ​major​ ​gaps​ ​are​ ​present.​ ​Many​ ​inductive arguments​ ​will​ ​be​ ​strong,​ ​but​ ​only​ ​​if​​ ​the​ ​premises​ ​aren’t​ ​missing​ ​anything​ ​or​ ​misguided.​ ​This​ ​is always​ ​possible​ ​with​ ​induction​ ​because​ ​it​ ​is​ ​always​ ​imperfect.

5. The​ ​following​ ​are​ ​short​ ​explanations​ ​and​ ​tools​ ​for​ ​three​ ​common​ ​types​ ​of​ ​induction​ ​and​ ​a​ ​fourth point​ ​on​ ​inference​ ​to​ ​the​ ​best​ ​explanation​ ​(theories).

a. Enumerative​ ​Induction​ ​(Generalization):​ ​uses​ ​parts/whole​ ​relations;​ ​“observed​ ​portion” i. Form:​ ​(P1)​ ​X​ ​percent​ ​of​ ​an​ ​observed​ ​sample​ ​group​ ​of​ ​a​ ​target​ ​group​ ​have​ ​a

particular​ ​property.​ ​(C)​ ​The​ ​target​ ​group​ ​probably​ ​has​ ​Y​ ​percent​ ​of​ ​that​ ​property. ii. To​ ​analyze,​ ​determine​ ​what​ ​the​ ​sample​ ​group,​ ​target​ ​group,​ ​and​ ​relevant​ ​property

are. iii. To​ ​evaluate,​ ​make​ ​sure​ ​that​ ​the​ ​sample​ ​is​ ​neither​ ​too-small/quantity​ ​(hasty

generalization)​ ​nor​ ​unrepresentative/quality​ ​(biased​ ​sample).​ ​If​ ​the​ ​argument​ ​is neither​ ​a​ ​hasty​ ​generalization​ ​nor​ ​biased​ ​sample,​ ​it​ ​is​ ​likely​ ​strong.

iv. If​ ​the​ ​target​ ​is​ ​more​ ​homogeneous​ ​in​ ​composition,​ ​the​ ​sample​ ​may​ ​be​ ​smaller. b. Analogical​ ​Induction:​ ​uses​ ​comparisons​ ​between​ ​the​ ​qualities​ ​of​ ​things;​ ​“alike”

i. Form:​ ​(P1)​ ​Thing​ ​A​ ​has​ ​properties​ ​1,​ ​2,​ ​3,​ ​4,​ ​5.​ ​(P2)​ ​Thing​ ​B​ ​has​ ​properties​ ​1,​ ​2, 3,​ ​4.​ ​(C)​ ​Thing​ ​B​ ​probably​ ​has​ ​property​ ​5.

ii. To​ ​analyze,​ ​determine​ ​what​ ​the​ ​compared​ ​things​ ​are,​ ​what​ ​shared​ ​properties​ ​are given,​ ​and​ ​which​ ​property​ ​is​ ​being​ ​extended.

iii. To​ ​evaluate,​ ​determine​ ​whether​ ​the​ ​argument​ ​is​ ​a​ ​faulty​ ​analogy​ ​or​ ​not:​ ​verify that​ ​the​ ​shared​ ​properties​ ​are​ ​relevant​ ​to​ ​the​ ​extended​ ​property,​ ​consider​ ​the​ ​ways in​ ​which​ ​the​ ​things​ ​are​ ​dissimilar​ ​and​ ​if​ ​this​ ​is​ ​significant,​ ​consider​ ​whether number​ ​of​ ​instances​ ​and​ ​diversity​ ​among​ ​cases​ ​is​ ​relevant​ ​to​ ​the​ ​argument.​ ​If

Prof.​ ​Eckel,​ ​U.​ ​Toledo,​ ​FA17

there’s​ ​no​ ​good​ ​reason​ ​to​ ​think​ ​the​ ​argument​ ​presents​ ​a​ ​faulty​ ​analogy,​ ​it​ ​is​ ​likely strong.

c. Causal​ ​Induction:​ ​uses​ ​patterns​ ​of​ ​causal​ ​relations​ ​between​ ​events​ ​in​ ​time;​ ​“X​ ​caused​ ​Y” i. Form:​ ​(P1;​ ​instance​ ​1)​ ​Factors​ ​A,​ ​B,​ ​C,​ ​and​ ​D​ ​precede​ ​event​ ​E.​ ​(P2;​ ​instance​ ​2)

Factors​ ​A​ ​and​ ​B​ ​precede​ ​non-E.​ ​(P3;​ ​instance​ ​3)​ ​An​ ​increase​ ​in​ ​C​ ​correlates​ ​with an​ ​increase​ ​in​ ​E.​ ​(P4;​ ​instance​ ​4)​ ​Factors​ ​C​ ​and​ ​F​ ​precede​ ​E.​ ​(C;​ ​inference)​ ​C​ ​is probably​ ​the​ ​cause​ ​of​ ​event​ ​E.

ii. To​ ​analyze,​ ​determine​ ​the​ ​instances​ ​and​ ​the​ ​range​ ​of​ ​factors​ ​and​ ​events​ ​present, determine​ ​the​ ​precise​ ​causal​ ​claim​ ​in​ ​the​ ​conclusion,​ ​determine​ ​which​ ​methods are​ ​employed​ ​(agreement,​ ​difference,​ ​joint,​ ​correlation),​ ​ask​ ​whether​ ​relevant factors​ ​are​ ​missing.

iii. To​ ​evaluate,​ ​determine​ ​whether​ ​relevant​ ​factors​ ​are​ ​misidentified,​ ​multiple factors​ ​are​ ​mishandled,​ ​coincidence​ ​is​ ​asserted​ ​as​ ​causal,​ ​correlations​ ​are assumed​ ​as​ ​causal​ ​relations,​ ​​post​ ​hoc​​ ​fallacy​ ​is​ ​present,​ ​cause​ ​and​ ​effect​ ​are confused​ ​or​ ​not.​ ​If​ ​not,​ ​the​ ​argument​ ​is​ ​likely​ ​strong.

d. Inference​ ​to​ ​the​ ​Best​ ​Explanation:​ ​uses​ ​theoretical​ ​explanations​ ​as​ ​accounts​ ​of​ ​events​ ​to argue​ ​that​ ​a​ ​theory​ ​is​ ​good​ ​or​ ​worth​ ​accepting​ ​as​ ​an​ ​account.

i. Form:​ ​(P1)​ ​Event​ ​E.​ ​(P2)​ ​Theory​ ​1​ ​is​ ​the​ ​best​ ​explanation​ ​for​ ​event​ ​E.​ ​(C) Theory​ ​1​ ​is​ ​probably​ ​an​ ​adequate​ ​account.

ii. Opposed​ ​to​ ​particular​ ​causal​ ​accounts,​ ​theories​ ​are​ ​general​ ​frameworks explaining​ ​why​ ​or​ ​how​ ​some​ ​class​ ​of​ ​instances​ ​is​ ​the​ ​case.​ ​Theories​ ​explain​ ​why or​ ​how​ ​something​ ​is​ ​the​ ​case;​ ​arguments​ ​assert​ ​that​ ​something​ ​is​ ​the​ ​case. Theories​ ​need​ ​to​ ​be​ ​asserted​ ​in​ ​the​ ​form​ ​of​ ​inference​ ​to​ ​the​ ​best​ ​explanation​ ​if they​ ​are​ ​to​ ​be​ ​advanced;​ ​otherwise,​ ​they​ ​remain​ ​speculative.

iii. The​ ​focus​ ​should​ ​be​ ​on​ ​theory​ ​as​ ​actual​ ​inference,​ ​not​ ​theoretical​ ​accounts​ ​that are​ ​procedural​ ​(How​ ​to​ ​do​ ​X),​ ​interpretive​ ​(What​ ​X​ ​means),​ ​functional​ ​(How​ ​X operates​ ​in​ ​a​ ​productive​ ​structure),​ ​or​ ​teleological​ ​(What​ ​X​ ​is​ ​for,​ ​its​ ​purpose​ ​or end).

iv. To​ ​analyze​ ​look​ ​for​ ​the​ ​event​ ​and​ ​proposed​ ​theory,​ ​​ ​understanding​ ​them​ ​as clearly​ ​as​ ​possible.

v. To​ ​evaluate,​ ​everything​ ​rests​ ​on​ ​P2,​ ​determining​ ​whether​ ​the​ ​theory​ ​is​ ​actually better​ ​than​ ​the​ ​competitors.​ ​First,​ ​make​ ​sure​ ​the​ ​theory​ ​is​ ​internally​ ​and externally​ ​consistent.​ ​Then,​ ​make​ ​sure​ ​the​ ​theory​ ​is​ ​the​ ​best​ ​because​ ​it​ ​ranks highest​ ​using​ ​the​ ​criteria​ ​for​ ​an​ ​adequate​ ​theory:​ ​testability,​ ​fruitfulness,​ ​scope, simplicity,​ ​conservatism.​ ​If​ ​P2​ ​is​ ​justifiably​ ​true,​ ​the​ ​argument​ ​is​ ​likely​ ​strong.

Prof.​ ​Eckel,​ ​U.​ ​Toledo,​ ​FA17