What is Philosophy?Introduction to Philosophy

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OverviewIBackgroundIITraditionsIIISubfieldsIVMajor periods in Western philosophy

Practice Quiz Hows your reading comprehension?1. Name the central claim that the authors defend in their introduction to philosophy (pp. 3-8).

2. Briefly summarize the main line of argument given in support of that claim.

3. The authors argue that the best way to read philosophy is:Passively, where the goal is to commit the most important terms to memorySkim and scan first, then read for detail after spotting main ideasAggressively, as an interested opponent to the authorTrick question: the authors dont tell you how to read philosophy

I. Background: What is Philosophy?Etymology: GreekPhilosophy = love (pursuit) of wisdomPhilo = loveSophia = wisdom

It asks the most basic questionsbig, fundamental questions about our universe, questions prior to all other disciplinesScope & implications

The Death of Socrates (1787)Jacques-Louis David

Philosophys scopePhilosophical questions areBroad questions about our universe to which we do or must presuppose some answersDifficult questions about everyday concepts

Philosophy as conceptual analysis: the analysis of concepts to gain knowledge/clarityConcept: an idea, especially of a class or set of particular objects/thingscarminddevicefreedompersonrights

Philosophy involves, centrally, the analysis of concepts that figure into every domain

What is philosophy?ArgumentationConceptualclarityPhilosophy:Argument about & assessment of fundamental concepts/ideas

Are there concepts in science & engineering in need of philosophical analysis?TechnologyInnovationScience/scientific methodMathematics/mathematical truthNumbersStatistical significanceProgressRightsMoral rightnessTruth

Are there any philosophical questions that arise in engineering?Why is technological progress a good thing?Can this technology be used immorally?What grounds my criteria for evaluating the success of my scientific theory?Will access to this technology be equitable?Am I obligated to consider all possible implications of my invention?Are mathematical truths objective?What kind of thing is a number? Are scientific generalizations truth-apt or merely more and less useful?What is the relationship between logic and mathematics?What is mathematic (or scientific) beauty?Does my theory presuppose a defensible view of reality?What is an explanation?Are there scientific laws?What grounds an inductive generalization?

ii. TraditionsCentral traditions in the history of philosophyMajor divides:A. Eastern & WesternB. Western: Continental & AnalyticC. Analytic: Naturalism & Non-Naturalism

Eastern Tradition1. Geographically: Asia, Middle East

2. Conceptually/methodologically: interest in universal patternsBlunted divide between the secular and religious

Western1. Geographically: Americas, Europe

2. Conceptually/methodologically:Influence of monotheismGod, creatorSharp divide between the secular and religious

A. Eastern & Western by comparison

Continental Philosophy

19th & 20th C. European philosophy

Term used by the analytic tradition to distance itself methodologicallynon-analytic philosophy (pejorative?)Negative definition

B. Western tradition: Continental & Analytic

Hegels (1770-1831) theory of reality set the stage for the development of the continental tradition and the eventual continental/analytic divide.

Basic Tenets:The goal of philosophy is to grasp the Absolute: an integrated unity of all that is real in experience

The method: Hegelian DialecticAny abstract idea, when fully considered, leads to its own negationIntegrating contradictionsThe contradiction yields a richer idea, which helps us grasp the AbsoluteHEGELS INTEGRATIVE PHILOSOPHYContinental Philosophers:

DerridaFichteFoucaultHeideggerHusserlKierkegaardSartreSchellingSchopenhauer

Analysis of argumentsForm: Logic (formal logic)

Emphasis on:Consistent reasoningDemonstrable conclusionsClarity & precision in language

Relationship with scientific inquiry:Influenced by scientific methodSystematic approach, precision, objectivitySolving problems by clearing away confusion, confounds, obscurityUnity with science: inquiry into the natural worldSimilar goals, different starting points and tools

Analytic PhilosophyRussell & Moore reacted to the Hegelian tradition by returning to a view of reality as a collection of atomic entities that we can analyze for clarity

III. Analytic philosophy: subfieldsLogicAssessment of argument form (structure)MetaphysicsEpistemologyPhilosophy ofLanguageScienceMindMorality (Ethics)Applied PhilosophyEducationEngineeringBusiness

Map of analytic Philosophy

IV. Periods in western philosophy 1 Ancient Philosophy2 Medieval (& Renaissance)3 Modern4 Contemporary

1. AncientLanguage: GreekTopics: All, especially political, ethics, metaphysics, and logicBig Names: Aristotle, Socrates, Plato

Raphael, School of Athens (1511)

2. Medieval & Renaissance (AD 300 1500s) Language: LatinTopics: Theology ( esp. Christianity), Faith vs. ReasonBig Names: Augustine, Aquinas, Anselm

3. ModernLanguages: Latin, German, French, EnglishTopics: Metaphysics & Epistemology, Ethics & Society, Mind Big Names: Descartes, Hume, Kant, Locke, Nietzsche

4. ContemporaryLanguage: English & GermanTopics: All, especially Logic & Math, Science, Metaphysics, Epistemology, and the analytic/continental divideBig Names: Russell & Whitehead, Quine, Carnap

Review questions1. What makes a question philosophical?2. What kind of analysis is central to the Western analytic tradition?3. Name two or three major traditional divides (divides by tradition).4. What are two of the main ways in which the Western and Eastern traditions differ?5. What is the relationship between analytic philosophy and science?6. Why are logic, metaphysics, and epistemology at the core of analytic philosophy?7. Name the four major periods in the development of Western philosophy.

The Methods of PhilosophyPart IIntroduction to Logic

overviewIBackground: Rhetoric & SophistryIIThe Development of LogicIIIFundamentals of LogicArguments, propositions, inferenceInductive and Deductive InferenceEvaluation: Validity, Soundness, Strength, and Weakness

Using arguments to advance, support, and criticize competing philosophical theoriesTheories about fundamental questions and conceptsConceptual analysis

Advancing a theory goes beyond merely asserting opinionIt involves giving reasons (in the form of arguments) to accept a claimCareful and systematic thinking about claims and conceptsI. Background:Format of Philosophical discourse

Rhetoric: The art of persuasion using language

Culture of Ancient Greece:Emphasis on political participationAthenian citizens present their own cases in courtLegal disputes often protracted

Result: Emergence of Sophistry:Professionalization of teaching rhetoric

History of argument

Sophist: (Greek) One who practices wisdomA group of teachers of rhetoric (~440 BC)Culture of Greece need for education in the art of persuasion

Sophists claimed to teach whatever it takes to be successfulLegallyCommerciallyPoliticallyMake the weaker argument the stronger(even when theres no argument at all)

Sophistry

The growth of rhetoric

Classical logicAncient GreeceAristotles syllogismGoal: understanding reason, the nature of inference

Contemporary logicBertrand RussellAnalytic PhilosophyGoal: understanding reason, the basis for scientific and mathematical inquiry

II. The Development of logic

RhetoricMake the weaker argument the strongerPersuasion getting a practical resultAppearance over Truth

LogicDistinguishing good from bad argumentsConsistency, objectivityTruthLogic vs. Rhetoric

III. Fundamentals

Logic: The study of the principles governing inference in an argument

Argument: A series of statements, where one is claimed to follow from (inferred from) the othersA set of claims containing an inference

Inference: The act of deriving one claim from another claim or set of claimsThe follow from part; the move in an argument

PropositionsProposition: The content of a statementPropositions may be asserted or deniedMust have a truth value: T or F

Propositions are the building blocks of arguments

Sentence: A unit of language expressing a complete thoughtSentences generally express propositionsThough the sentence is technically distinct from the propositionThe sentence is the vehicle for the proposition

Propositions vs. Sentences

Sentences are the vehicles that carry propositionsWe use sentences to express ideas, or propositions, but they are not the same thing:It is rainingEs regnetEsta lloviendo

3 different sentences Each asserts the same proposition

From Propositions to ArgumentsArgument: a group of propositions of which one is claimed to follow from the others

Premises: A proposition or set of propositions used to make an inference to a conclusionThe support for the conclusion

Conclusion:A proposition that is claimed to follow from a set of premisesThe part of the argument that you infer from the premises

Premises and conclusions

Conclusions often indicated by:Therefore, thus, hence, consequently, it follows that, then, this entails that, etc.

Premises often indicated by:Because, as, for, since, given that, etc.

Extended & Simple Arguments

Extended argumentsContain other arguments within them

Simple argumentsDo not contain other arguments within them

Most philosophical articles contain extended arguments

Extended arguments are only as good as their componentsMust be broken down and analyzedA complex argument is only as good as its weakest inference

InferenceThe process of reasoning from a set of premises to a conclusionThe inference is the act of drawing a conclusion from a set of premises or supporting claims(The conclusion is sometimes also called the inference)

Broadly, two kinds of inference (or reasoning):DeductiveInductive

Logic evaluates quality of inferences

III. InferenceTwo Kinds of Inference:Deductive inferenceAttempts to show that the conclusion must follow from the premises the argument guarantees the conclusionConclusion follows necessarilyE.g: Mathematics uses deductive inference

Inductive inference (non-deductive)Attempts to show that the conclusion probably follows from the premisesThe argument is intended to make the conclusion likelyE.g. science uses inductive inference

Evaluating InferencesInference correctly links premises and conclusion

Deductive arguments: attempt to guarantee conclusionValid = good deductive inferenceInvalid = bad deductive inference

Inductive arguments: attempt to make conclusion likelyStrong = good inductive inferenceWeak = bad inductive inference

Deductive ArgumentsAttempt to guarantee the truth of the conclusionUse a set of premises to derive a conclusion

2 things to evaluate:The inferenceThe process of reasoning, or movement from premises to conclusion (validity)The contentThe truth of the premises themselves (soundness)

Evaluating Deduction - Step 1

Validity:A property of deductive argumentsDf: An argument is valid if the truth of the premises would guarantee the truth of the conclusion

Assuming the premises are true, is the conclusion a necessary result?Yes: Valid argumentNo: Invalid argument

Step 2: SoundnessThe argument is valid, but are the premises actually true?

That requires looking at the content of the argument

Soundness:1. Validity: if premises are true, conclusion is true; and2. All true premises

A deductive argument is sound when it is valid AND the premises are actually true.

When a deductive argument is sound, the conclusion must be true it cannot be any other way.

Necessary & Sufficient conditionsNecessary condition: must be satisfied for statement to be trueSufficient condition: if satisfied, ensures a statements truth

Validity is a necessary condition (NC) for soundnessAll sound arguments are valid argumentsBut not all valid arguments are sound

Validity is not a sufficient condition (SC) for soundness

Example Deductive ArgumentAll human beings are mortal.Socrates is a human being.Therefore, Socrates is mortal.

Step 1: If the premises were true, must the conclusion be?Step 2: Are the premises actually true?

Evaluating Inductive ArgumentsIt is not possible for inductive arguments to guarantee a conclusionHence scientific hypotheses are always strong/weak, not T or F

Instead, inductive arguments make the conclusion probable or likely

Evaluation:Do the premises make the conclusion likely?Yes: Inductively strongNo: Inductively weak

Example Inductive ArgumentRaven #1 is black.Raven #2 is black.Raven #3 is black.In fact, any raven I have ever seen is black.Therefore, all ravens are black.

Evaluation: how likely is the conclusion given the premises?

Induction vs. DeductionWhat is the primary difference?Deduction: GuaranteeInduction: Probability

Deduction doesnt try to go far beyond the available factsMoves stepwise to available informationAnalysis of what you already know

Induction goes beyond the available facts Draws conclusions about the unobserved on the basis of the observed

Induction vs. DeductionDeduction: from general principles to particular casesReasoning from general to specificGeometric proofs are deductive because they are an attempt to show that what is true of triangles in general is true of this particular triangle, T.

Induction: from particular cases to general principlesReasoning from specific to general

Science is often inductive because it goes beyond the evidenceIt reasons from specific cases to generalizations about the way the world works

Inductive or deductive inference?

Only wrapped textbooks may be returnedYour textbook is unwrappedTherefore, your textbook may not be returned.

Inductive or deductive?

Jimmy is a great student in the front rowJamal is a great student in the front rowSusan is a great student in the front rowThe best students always sit in the front row

Inductive or deductive?

Students sitting in the front row are probably among the best studentsJimmy is sitting in the front rowJimmy is probably one of the best students.

Inference review questions(1) What is an inference, in general, in the philosophical sense? Use at least the following three words in your answer: proposition, premises conclusion. (2) What kind of inference is used in the argument below? (3) How do you know its that kind of inference as opposed to some other? (4) Evaluate the following inference using the terminology appropriate for the kind of inference you named in (b).P1. The only members of the Williams family are Susan, Nathan and Alexander.P2. Susan wears glasses.P3. Nathan wears glasses.P4. Alexander wears glasses. Therefore, all members of the Williams family wear glasses.(5) Write up one example of a deductive inference with at least 2 premises(6) Write up one example of an inductive inference that could be mistaken for a deductive inference

HOMEWORK: week 1Answer the following questions (numbered accordingly) on an MS Word document, include your name, and submit to the homework drop box before Thursday @ noon.

1. Specifically, what kind (or style) of philosophy are we doing in this course, and why is logic important to it? Explain using the appropriate vocabulary

2. Using the appropriate terminology, evaluate the following argument:All dogs are mammalsAll mammals have two legsTherefore, all dogs have two legs

3. Explain the difference between deductive and inductive arguments

The Methods of PhilosophyPart II: Inference & FallaciesIntroduction to Logic

Rules of InferenceIn deductive logic, we construct formal proofs of validityInference rules are rules that may be used in this processThey are valid argument forms

Some Valid Rules of InferenceModus Ponens (MP)PQPTherefore Q

Modus Tollens (MT)PQ~QTherefore ~P

More Valid Rules of InferenceHypothetical Syllogism (HS)PQQRTherefore PR

Disjunctive SyllogismP or Q~QTherefore P

Bad ArgumentsBad or fallacious argumentsInvalidAnd thus also unsound

Fallacy: a mistake in reasoningFormal fallacy: deductive argument with invalid formInformal fallacy: flawed reasoning, but the flaw is not the form of the argument

Formal FallaciesLogical fallacies

A flaw in the structure of a deductive argument

But presence of a fallacy says nothing about truth values of premises or conclusionBoth could be true, but the conclusion does not follow from premises

Example Formal Fallacy:Affirming the consequent

If P then QQTherefore, P

If Jones is bifurcated by shark, then hes deadJones is deadTherefore, Jones was bifurcated by shark

ExampleDenying the antecedentIf P then QNot PTherefore Not Q

If Jones is bifurcated, then he is deadJones is not bifurcatedTherefore, Jones is not dead

Informal Fallacies

Flaw is not in the form, but rather in the content of the propositions

logical fallacy can refer to formal or informal, but informal fallacies are probably more common

4 general types of informal fallacy:Fallacies of relevanceBad inductionFallacies of presumptionFallacies of ambiguity

Fallacies of RelevanceRed herringAn argument that attacks some feature of an idea or program that isnt any part of the program at allAn attempt to distract us from the real issue

Example: CA attempts ban on plastic bagsCommercial by American Chemical Council: California is in trouble: 2.3 million unemployed, a $19 billion deficit. And what are some California politicians focused on? Grocery bags.

Fallacies of Relevance

Fallacies of RelevanceMotive fallacy:A variant of ad hominemArgument against an idea on the grounds that the person proposing it has ulterior motivesNot relevant to the idea they are defending

Political motivesPoliticians constantly accusing each other of having political motivesOf course they do! But thats not what makes the policy they are proposing crappy

Fallacies of PresumptionBegging the QuestionAssuming the truth of what you seek to prove in order to prove itOften the conclusion is disguised in alternate language in the premisesTo allow every man unbounded freedom of speech must always be, on the whole, advantageous to the state; for it is highly conducive to the interests of the community that each individual should enjoy a liberty, perfectly unlimited, of expressing his sentiments.

Fallacies of AmbiguityEquivocationTo confuse several meanings of a word or phrase in the context of an argumentE.g., a feather is light so it cannot be dark

1. If someone is entitled to an opinion, then her opinion is well supported by the evidence2. I am entitled to my opinion (like everyone in a democratic society that values free speech)3. Therefore, my opinion is well supported by the evidence

Welcome to IA101 Introduction to Philosophy. This is your first lecture. Read along with these lecture notes as you work through the slides. You should use these lectures in conjunction with your readings. Ideally, you should read the required assignments for the week before you attempt to use these lectures.*Important notes on how to use these slides, and how to complete lecture-based homework.*These are the topics covered in this lecture.*If youre using your textbook appropriately, you should be able to answer this question. If you cant youre not reading carefully enough, and thats likely to hurt the quality of your papers and discussion board comments. Reading carefully, and retaining relevant information, is essential to success in this course.*Philosophy is an academic discipline that concerns itself with posing and attempting to answer the most fundamental questions about the universe that we can think of. In biology, you might study genes, for example. In philosophy (philosophy of science), you might ask big fundamental questions about such sciences, like, are genes real things, or just convenient ways for scientists to refer to clusters of molecules? This is the sense in which philosophy asks about very basic, very fundamental questions. Often, these are the hardest to answer. We try to answer them by clarifying familiar concepts (like gene or molecule, or science, or God, etc.).*The practice of analyzing concepts (or ideas and categories of ideas) carefully is called conceptual analysis. It is one of the tools that philosophers use to make progress on tough questions. Its not the only method philosophers use, however. They also make relevant distinctions, question assumptions, and sometimes consider how scientific or empirical evidence might help with a very basic question about our universe.*In philosophy, we take positions on big fundamental questions by posing arguments that defend positions on those questions. Those positions are informed by careful analysis.*Philosophy is not a discipline without practical relevance. Many areas of inquiry, including science, math, and engineering, would benefit from learning to be more careful and systematic in thinking about concepts. Here is a simple example: at Rose-Hulman we hear a lot about the value of innovation. Have you ever stopped to ask why innovation must necessarily be a good thing? What it presupposes to say that innovation is always good? Are there times when innovating isnt necessarily the best thing one could do? These are all philosophical questions that have practical implications. This list on this slide provides some other examples.*Here are more philosophical questions that engineers and scientists and mathematicians would benefit from thinking about. Even if you cant answer these questions, its important to learn how to ask them.*To understand philosophy as an academic discipline, you should know some things about the history of the discipline. Here Im going to provide a simple overview of the discipline using three basic distinctions. The first is geographic: there are differences in Western hemisphere and Eastern hemisphere philosophy. There are also different kinds of philosophy within the Western hemisphere (where North America is). Finally, there are even differences in kinds (or styles) of philosophy within the analytic and western traditions. Its important to note that these distinctions are simplifications, but theyre a useful framework for understanding the different kinds of academic philosophy one could encounter in the world.*Some of the major differences in academic philosophy across hemispheres have to do with how philosophers view the world. In eastern philosophical traditions, philosophers often look for universal patterns. Sometimes eastern traditions seem to focus on the interconnectedness of everything in the universe. By contrast, Western approaches tend to focus on analyzing individual events. These are very vague and broad generalizations. Thats because any such attempt to generalize across all schools of philosophical thought are bound to fail. But in general, its simply worth recognizing that there are some differences in styles across hemispheres. As we begin doing philosophy in this course, you can start thinking about what kind of philosophical style were using. *Within the western tradition (which includes Europe, the US, and Australia among other places where philosophy is prominent), one style of philosophy is called continental. The term comes from a reference to the European continent or the European mainland. The term is vague, but its meant to depict styles of doing philosophy that focus on history (historicism), reject scientism (the dominance of science in inquiring about the world), and tend not to place a major emphasis on formal logic. Much continental philosophy begins with Hegel, a German philosopher who was famous for his historicist and idealist account of reality. Youll get a sense for Hegels ideas by looking at the Internet Encyclopedia of Philosophys entry on Hegel. Its a bit confusing, and the subject could occupy a whole course, but youll quickly get a sense for the continental flavor of Hegels ideas. *Here are some of Hegels ideas. It is to these ideas (and others) that much of continental philosophy is reacting. In fact, much of analytic philosophy is also a reaction to Hegel. Analytic philosophy, in some sense, is a negative reaction to Hegel: the lack of clarity in these ideas led to a movement focused on clarity and logical argumentation and rigor. Our introduction to philosophy is actually an introduction to Western analytic philosophy, more specifically.*Within the Western tradition, the contrast to the continental style is the analytic style of philosophy. Analytic philosophy tends to focus on logical analysis of arguments. Logic is a formal method for evaluating arguments. You may already be familiar with some kinds of logic from mathematics and computer science. The analytic tradition also tends to focus on the relationship between philosophy and science. The philosophical problem of determining where philosophy ends and science begins is famously called the demarcation problem. Its very hard to specify exactly what makes a question scientific rather than philosophical. Some of the clearest examples of the difficulty tend to arise in theoretical physics. But they arise in lots of other places too, including at the boundaries of moral philosophy and scientific psychology and neuroscience.*Analytic philosophy involves careful analysis of all kinds of problems. It includes logic: the study of argument structure; metaphysics: the study of what exists; epistemology: the study of knowledge and what and how we can know; philosophy of language: what is language and what can it reveal about the world?; philosophy of science: what is science, how is it different from philosophy? Are scientific concepts real things in the world or just convenient fictions that scientists use? Etc.*Analytic philosophy has a particular organizational structure, which places the core parts of philosophy at the center. They are central because all other fields of philosophy invoke them. Logic is central because all fields of analytic philosophy use argumentation, and so must use the formal study of arguments. Metaphysics is central because all fields of philosophy presuppose or deal with questions about what exists. Epistemology is central because all philosophical arguments make claims about what we can know and how we can know it (even if they claim that we cant know anything at all! a position called skepticism in epistemology).*Lets turn now to some history. Western philosophy can be divided, historically, into periods. Here are four broad periods.*600 BC is about 2,700 years ago. By contrast, anthropologists place the first modern human at approximate 200,000 years ago. Philosophy is as old as civilization.

Socrates was a prominent ancient Greek philosopher. Hes most famous for the elenchus, a pedagogical technique aka the Socratic method in which you use a series of questions to bring someone to see a new point or idea, or to teach them. One of the other notable ideas to come from Socrates is the humble notion that being wise may mean being aware of your own ignorance. As the story goes, one of his friends asked the Oracle at Delphi whether there was anyone wiser than Socrates, to which the Oracle replied no one. Socrates regarded the idea as paradoxical because he knew the great limits of his knowledge. He then questioned some of the wisest Atheniens to determine how much they knew, and came to the conclusion that he was the wisest precisely because he acknowledged his own ignorance. In the process he upset many powerful and rich people, who ultimately conspired to charge him with corrupting the youth. He defended himself on trial by citing the troubles of old age and the benefits of dying and was sentenced to death by drinking Hemlock.*Aristotle and Plato in the center.*Medieval philosophy is philosophy during the dark ages, in which Christianity was the dominant Western mode of thought. Many important thinkers, most notably St. Thomas Aquinas, worked in the medieval period. Many medieval philosophers, especially Aquinas, were concerned with explaining the relationship between Christian faith and human reason. Faith is believing in something in the absence of reasons to believe in it. Yet philosophy is concerned with the power of human reason and what it can tell us about our world. How is it possible to square these? This was an important question. Many in the Church were leery of human reason, since it could lead thinkers to reject religious dogma.

Manichaeism was a major Iranian Gnostic religion. It was memorable for its colorful account of the origin of the universe (cosmology), which had to do with a struggle between light and dark. Predominantly lasted between 3rd and 7th Centuries. Probably died out by the 14th Century in China. The founding prophet was Mani. Perhaps most notable about this religion is its striking similarities with Christianity, including similarities between Mani and Jesus.*Interesting things to think about: the development of the scientific method has its origins all the way back in the Ancient Greeks, most notably Aristotle. Though it developed over the centuries, up to something near its present form in Bacons time, its history is tied up with the history of philosophy.

That each major historical event is connected with a major movement or issue in philosophy, or the history of ideas.

Modern philosophy is philosophy that begins with the renaissance and enlightenment period, in which reason came to rule over religious faith once again, especially in Europe. Modern philosophers went back to thinking about big foundational questions, like what exists? and how do we know? and what is morality?

*Contemporary philosophy is todays philosophy. This is our period. It began around1900 (arbitrary date, really). It does not differ significantly from Modern philosophy its just more contemporary. The same questions that interested the moderns still interest us today. One difference, however, is that we have made significant advances in science, technology, math, and medicine since the age of the moderns. This has no doubt complicated some issues in philosophy, and perhaps clarified or changed others.*You should now be able to answer these questions in fairly simple terms.*Logic is the method of analyzing arguments. Philosophers rely on logic to distinguish good from bad arguments. So it is essential to this course that you understand some very basic things about logic.*Heres what well cover in these slides on logic.*We give arguments in philosophy in order to defend positions on philosophical questions. Arguments are structures that support conclusions.*You should understand the difference between logic and rhetoric. The goal of rhetoric is to get people to believe you, even in the absence of good evidence or arguments. The goal of logic, with which philosophy is concerned, is to distinguish good and bad arguments. This is important: philosophers use logic, not rhetoric, because the goal is to discover truths about the universe, not to just get people to believe you even when youre wrong. Lawyers and politicians rely on rhetoric because their jobs depend on getting people to believe them, even when the evidence is not on their side. Someone who is genuinely philosophical cares about uncovering the truth, not just about appearing smart, or being right, or being persuasive.*In this sense, sophistry is anti-intellectual. The second picture here, with President Obama pictured, is itself a piece of sophistry. Without providing any argument, it attempts to convince you that President Obama is a sophist (a trickster). The picture is thus ironic (or hypocritical): it is attempting to accuse President Obama of engaging in sophistry by employing sophistry itself. Whoever made this picture is not particularly bright, regardless of his or her political opinions. One may like or dislike President Obamas policies, but sophistry of this sort does nothing to advance an intelligent argument about those policies. *These days, political rhetoric is everywhere. There is precious little genuine philosophy in public life or politics.*Logic developed as a way of sorting out good arguments from bad arguments. Its origins are in ancient Greece. Aristotle developed much of the system of logic that we still use today.*Definitions you need to know. Commit these to memory.*More definitions.*When reading a philosophical article, its pretty easy to spot conclusions. therefore is a tipoff that a conclusion follows.*Sometimes arguments are long and complex, and even made up of smaller arguments. But the principles of logic still work the same way. They govern all arguments, big and small, complex and simple.*An inference, just as in math, is an act of reasoning. Its the process of moving from one set of statements (premises) to another (conclusion).

Please note that all of these terms are technical terms in philosophy, and you need to use them accurately in your own writing and comments.*There are two kinds of inference: deductive and non-deductive. The non-deductive kind is, for our purposes, inductive.*These are terms that apply to inferences in arguments. Note: they do NOT properly apply to conclusions. Conclusions are not valid or invalid, they are true or false. But the inferences that yield those conclusions are valid or invalid. It makes sense to say that Smiths argument is invalid. It does not make sense to say Smiths conclusion is invalid. By now, you should understand why. Answer: because conclusions dont contain inferences.*Heres how you should think about evaluating deductive arguments. There are two things to evaluate in any given deductive argument: the quality of the inference (valid/invalid) and the content of the argument itself (are the premises true or false?)*Validity is a property of inferences in arguments. Valid inferences are those in which the truth of the premises would guarantee the truth of the conclusion.*We say that an argument is sound if (1) it is valid, and (2) it has all true premises.*Thus, validity is a necessary condition for soundness. All sound arguments are valid arguments with all true premises.*Lets look at some simple examples so that we can understand how to evaluate arguments using the appropriate terminology. This is a deductive argument.*This is an example of an inductive (non-deductive) argument.*You should understand the difference between a deductive and inductive argument. Remember: validity only applies to deductive arguments.*That is why we evaluate these different kinds of argument differently.*You should be able to answer this question now

Answer: deductive.*

Answer: Inductive*

Deductive. Dont be fooled by probably. The structure of the argument is such that if (1) and (2) are true then (3) must be true. The argument would guarantee that Jimmy is probably one of the best students.**Onto Part II of the introduction to logic. This part deals with common patterns in reasoning that we can give names to. When people make mistakes in reasoning in the same ways over and over again, we can give those mistakes names. Thus we give names to different logical fallacies (or mistakes).*Modus Ponens is a valid (good) pattern of reasoning: It says if P, then Q; P; Therefore, Q

Modus Tollens is also a valid pattern of reasoning: It says If P then Q; Not Q; Therefore, not P

Notice that arrows are read if/then*The point is to teach you that you can recognize basic patterns in reasoning in ordinary arguments. This argument about Jones and the shark takes the invalid pattern called affirming the consequent. You can see that the argument is invalid by just thinking through it: the fact that Jones is dead does not guarantee that he was bifurcated by shark because there are other ways to die (perhaps he was hit by a bus).

A valid argument guarantees the truth of the conclusion. But here, notice that the two premises could be true and the conclusion could still be false. That means the argument is invalid.*The difference between formal fallacies and informal fallacies is simple. Formal fallacies are mistakes in the form of an argument. Informal fallacies are not mistakes in form but rather mistakes in the way that the words in the argument are being used.*Entitled in (1) means something different from entitled in (2), which allows us to draw a conclusion which we would not be able to draw had we kept the meaning of the term constant.*