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How to Think: Introduction to Logic, Lecture 7 with David Gordon - Mises Academy

on Jun 26, 2013

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How to Think: Introduction to Logic, Lecture 7 with David Gordon - Mises AcademyPresentation Transcript

• Lecture 7Induction
• What Is Induction?• In deduction, we move from premises toconclusion. But where do the premisescome from?• One way is through analytic judgments,e.g., “All triangles are three-sided figures”.• In an analytic judgment , the subject andpredicate are logically connected.
• Analytic Judgments and AustrianEconomics• Much of Austrian economics, as developedby Mises, consists of analytic judgmentsand deductions from them.• Some example: Every action uses means toachieve ends• An actor always chooses his most highly-valued end.
• Learning From Experience• Induction concerns truths that are notanalytic judgments. These are learned fromexperience.• How do we know, e.g., that people need toeat in order to live? This isn’t somethingthat we deduce from the concept of “humanbeings” or “eating food.”
• Why Induction Is a Problem• Experience is always about particular eventsat a particular time. (This is a conceptualtruth.) How can we get a universally trueproposition from such experience?• Suppose, e.g., that we have found on anumber of occasions that waters runsdownhill. What justifies the generalization,“Water always runs downhill?”
• Joyce’s Answer to the Problem ofInduction• There isn’t a generally accepted answer to thisproblem.• Joyce’s solution depends on the fact that thegeneralizations we make from experience areabout causes. By “cause” he means the reason forsomething, i.e., what makes a thing to be what itis.• Joyce’s approach is quite similar to the “new”approach to induction offered by Leonard Peikoffin David Harriman, The Logical Leap.
• Joyce’s Answer Continued• Sometimes we can recognize a causal relationshipimmediately. For example, I grasp immediatelythat I caused the previous slide to shift to this one.• Sometimes it is very difficult to find out what thecause of something is. For example, there are allsorts of things that take place once I click themouse that bring about the slide’s movement. Youhave to know a great deal to discover these.
• Types of Cause• Joyce takes an Aristotelian approach tocausality.• In this view, there are four types of cause:• Final• Formal• Material• Efficient
• Final Cause• The final cause of something is its purpose.• In the Aristotelian view, purposes aren’tconfined to human action.• This doesn’t mean everything has a mind.Rather, everything has a natural end. Forexample, the purpose of the heart is to pumpblood.
• Formal and Material Causes• The formal cause is the shape of something, Joycegives the example of the shape of a statue.• The material cause is what something is a madeof. For example, the material cause of a marblestatue is the marble that makes up the statue.• The formal and material causes are called intrinsiccauses. They make no reference to anythingoutside the thing whose causes they are.
• Efficient Cause• The efficient cause is the closest to the modernconception of cause. It is what brings about achange.• In the example of changing the slides, I am theefficient cause, because I brought about thechange from one slide to the next.• In the Scholastic view, the efficient cause is asubstance, not an event. This contrasts with theviews of most modern philosophers.
• More About Causes• The final and efficient causes are calledextrinsic causes because they refer to whatis outside the object. For the final cause,this is the end, or aim, of the object. For theefficient cause, it is the substance thatbrings about a change in the object.
• How Does Joyce Solve theProblem of Induction?• We know what to look for when we aretrying to discover the cause of something.Depending on the situation, it can be any ofthe four causes.• But how does this help us solve the problemof induction? That is, how will it enable tocome up with universal causalgeneralizations?
• Abstraction• When you arrive at a cause of something, you canabstract from the particular details of the instanceyou are considering.• In the example of changing the slides, I canabstract from saying that clicking the mouse thistime caused this slide to move. I can say, “clickingthe mouse will cause a slide to move”, withoutreferring to a particular occasion.
• The Uniformity of Nature• Even if you abstract from particular causaloccasions, though, how does this solve theproblem of induction? How do you know that theabstract causal statement will always apply?• Joyce appeals to the principle of the uniformity ofnature: the same cause will under the samecircumstances produce the same effect.• This principle, he claims, is a metaphysicalprinciple that applies to the physical world.
• A Mistake About the UniformityPrinciple• According to Joyce, this would be a wrongway to reason:• Nature is uniform• On various occasions, my clicking themouse causes a slide to move• Clicking the mouse in the rightcircumstances will always cause a slide tomove.
• What’s the Mistake?• Once I say that my clicking the mousecauses the slide to move, i.e, then I havealready appealed to uniformity. That is, Ihave claimed that it is in the nature ofclicking the mouse in the appropriatecircumstances that as a result a slide willmove. I’m already relying on uniformity, soI don’t need to bring it in as the majorpremise of a syllogism.
• The Inductive Syllogism• This is different from ordinary induction.• In an inductive syllogism, if something applies toall the logical parts of a whole, it is true of thewhole.• This is sometimes used in geometry.• The conclusion doesn’t establish a logicalconnection between the nature of the wholesubject and the property attributed to it. Theproperty might apply to each of the parts indifferent ways.
• Perfect and imperfect Induction• This is another type of induction. In thistype, you enumerate, i.e., list the instancesin a certain whole that possess a certainproperty. You conclude that every instancehas the property. Note the difference fromthe inductive syllogism, which is aboutlogical parts---sub-types---of a whole, notinstances.
• Perfect and Imperfect InductionContinued• If you enumerate every instance, theinduction is called perfect and is valid.Suppose I ask each student in this class,“Are you interested in logic?” and everyonesays yes. Then I can conclude everyone inthe class is interested in logic.• If I generalize from a few instances, theinduction is imperfect and isn’t worth much.
• Hume on Induction• Joyce’s Scholastic account wouldn’t beaccepted by most modern philosophers whowork on induction.• They have been influenced by a famousargument of David Hume• Hume denied that the principle of theuniformity of nature could be established byreason. Induction rests on habit
• Hume’s Argument• Hume said that if the principle of uniformity couldbe rationally established, this would be either byreason or experience.• It isn’t contradictory to deny uniformity. Thus, theprinciple isn’t a truth of reason.• If we say experience supports it, because the samecauses have been observed to have the sameeffects in the past, how does this justify aninference to the future? It can do so only ifuniformity is already assumed.
• Karl Popper’s Radical Approach• Popper accepts Hume’s argument• His response is that we don’t need induction. Wedon’t need to say that from the fact that a numberof instances of a causal relation have beenobserved, we are justified in inferring a causallaw.• He says that we come up with a hypothesis thatcan be falsified. We don’t need anything more inscience.
• Objections to Popper• On Popper’s view, we can say that a theoryhasn’t yet been falsified, but this gives us nogrounds to expect that it will continue to betrue in future.• This is a skeptical view. We don’t know,e.g., that stepping in front of a speeding carwill have bad consequences for you if youdo it.
• Example of a Fallacy• Christopher Weldy has sent in this case:• “Do you realize that anything which applies to thegovernment also applies to God. That thegovernment is the one earthly entity that closestresembles God. If obeying to the government, ifblind faith and blind obedience in the governmentis wrong, same thing goes for God.”• He asks, Is this an example of Begging theQuestion?
• What’s Wrong with theArgument?• This isn’t strictly a case of begging the question,because the argument doesn’t start with thepremise that not obeying the state is like notobeying God, and then conclude to this sameproposition.• But it assumes a controversial premise—the stateis like God---that only those who already rejectdisobedience are likely to accept.
• Another Example• One person wondered whether the argument wehave just discussed has an undistributed middleterm. I don’t think so.• This example is also from Christopher:• “You see the word obedience appear a lot in theBible and you see Christians use the wordobedience a lot. The last time a charismatic personused the word “obey” and “obedience” as often asthe Christians do, a second world war erupted. Isay, let’s get rid of both, the government andChristianity and all other religions for all I care.”
• The Fallacy Exposed• As Michael Ronnall suggests, this argumentcommits a post hoc, ergo propter hoc fallacy.• The last time a charismatic person used the word“obey” and “obedience” as often as the Christiansdo, a second world war erupted• Just because the war came after the use of“obedience”, it doesn’t follow that using this wordcaused the war.