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NARRATOR: We all agree that there are atomic bombs,but can be sure that there are atoms?They're too small to see.They exist only in theory.We think all matter is made up of atoms,but can we know that is true?What does it mean to say that anything is true?

NARRATOR [continued]: [MUSIC PLAYING]

NARRATOR [continued]: [The Examined Life][Does Science Give us Truth?]

JOHN SEARLE: In philosophy, thereare certain default opinions.There are certain opinions that everybody has to start fromand everybody, in the end, goes back to.The default position about truth, the one that we allhad before we ever started doing philosophyis the idea that if a statement'strue-- I say snow is white or the cat's on the mat or the sun

JOHN SEARLE [continued]: is 93 million miles away from the Earth--those statements are true, because there'ssomething in the world that makes them true.There's something in virtue of which they are true.There's something in the world they correspond to.

ARTHUR FINE: Correspondence theory of truthsays that a thought, a sentence, an assertion, an idea, if youlike, is true, just in case it correspondsto some feature of the world.Someone thinks of correspondence account of truthas positing a relation between, on the one hand,linguistic objects or, perhaps, mental object

ARTHUR FINE [continued]: sentences or thoughts, something of that kind,and on the other hand, something that's extra mental,something that extra linguistic, so some feature,aspect, thing out there in the world.[EXPLOSIONS]

NARRATOR: The correspondence theory of truthtakes the position that there is a reality in the world.We discover that reality and make statements about it,and truth emerges from how well those statements correspondto reality.

NARRATOR [continued]: An approach to science called scientific realismtakes a similar position.Science discovers reality.Scientific theories are true when they describe realityaccurately.

ARTHUR FINE: So realism says on the one hand,certain things do exist.They have a certain character, and on the other hand,we can come to know that.We can have access to it in terms of our own knowledgeand understanding by means of the sciences.

NARRATOR: Philosopher Karl Popperexpresses a realist view on how sciencehones in on the true nature of reality.

KARL POPPER: Although I do not think that we can everdescribe by a universal laws an ultimate essence of the world,I do not doubt that we may seek to probe deeper and deeperinto the structure of our world, or as wemight say, into properties of the world thatare more and more essential, or of greater and greater depth.

KARL POPPER [continued]: Every time we proceed to explain some conjecture of lawor theory by a new conjectural theory of a higherdegree of universality, we are discovering moreabout the world trying to penetrate deeperinto its secrets.

NARRATOR: One challenge that has beenposed to correspondence theory and scientific realismis that they are limited.They don't cover all the situations in whichpeople commonly refer to truth.

DH MELLOR: What makes a logical statementor a mathematical statement true isn't in any very obvious waythat it corresponds to something out there in the world thatmight not have been out there.So you need a special account of truth in logic and mathematics.

HILARY PUTNAM: Anything that's within the scopeof rational thinking, in particular of logic,is subject to being called true or false.I don't think that everything thatis subject to being true or false in that senseis a description, and I think as longas we think that everything that's true or falsehas to be a description of somewhere,

HILARY PUTNAM [continued]: we won't understand ethical truth.We won't understand logical truth.We won't understand mathematical truth.

NARRATOR: A theory of truth that many peoplefind more applicable in these kinds of situationsis called the coherence theory.It maintains that an idea is truewhen it coheres with or fits in with other ideas.Brand Blanshard gives an example.

BRAND BLANSHARD: It is, perhaps, in such systems as Euclideangeometry, that we get the most perfect examples of coherencethat have been constructed.If any proposition were lacking, itcould be supplied from the rest.If any were altered, the repercussionswould be felt through the length and breadth of the system.

JOHN SEARLE: The coherence theory was part of idealism.Idealism, remember, says there is no real world.There's just our system of representations.Well, then, what's truth?If there's no real world, well, truth justconsists in how our various beliefs and thoughtsand judgments cohere with each other.

NARRATOR: Coherence theories don't necessarilycontend that truth depends entirelyon coherence among ideas.They can, for instance, say, look at scientists.How much of what they do depends on describing reality,and how much depends on getting their ideas to cohere?

RICHARD RORTY: When a scientist goesthrough a process of empirical confirmation of a theoryand praises it as the best candidateamong the available theories, he doesn't compare the theorywith reality, except in this highly indirect wayof making it square with the beliefswhich reality has forced him to acquire.

RICHARD RORTY [continued]: And if a philosopher comes along and says,given that the relation between your theory and realityis this incredibly complex, indirect thing, whydo you think your theory is true of reality?The scientist should tell the philosopher, look,this is what we mean by a theory being true of reality.

RICHARD RORTY [continued]: It's just a theory, which rendersas many beliefs coherent as possible.What more do you want?

NARRATOR: The idea that scientific theoriesare considered true because they cohere with other theories wasvoiced most forcefully by Thomas Kuhn in his 1962book, The Structure of Scientific Revolutions.

WOMAN: Two days worth of earthquakes, September 9.

NARRATOR: In Kuhn's view, every scientistworks within a conceptual framework called a paradigm.A community of scientists agree about that paradigmand use it as a foundation for their work.A new theory is true for them, onlyif it fits into this paradigm.

ARTHUR FINE: I like to call these thingsconsensus theories of truth.They come in different varieties and flavors,but the basic idea is always the same,namely that an assertion, a sentence, an idea, a thought,a theory, if you like, is true, justin case the right people believe it or would believe itunder the right circumstances.And that's, of course, entirely a human-centered concept

ARTHUR FINE [continued]: of truth.

NARRATOR: The belief that truth is human-centered contradictsthe realist belief that science cancapture the reality of nature in theories.Thomas Kuhn describes the conflict.

THOMAS KUHN: We're all deeply accustomed to seeing scienceas the one enterprise that draws constantlynearer to some goal set by nature in advance,but need there be any such goal?Can it not account for both science's existenceand its success in terms of evolutionfrom the community's state of knowledge at any given time?

THOMAS KUHN [continued]: Does it really help to imagine that thereis some one, full objective true account of nature,and that the proper measure of scientific achievementis the extent to which it brings uscloser to that ultimate goal?

RICHARD RORTY: Yeah, I think the whole idea of one truthis a bad leftover of Greek metaphysicsand Christian theology.I think the notion of one truth is basicallyjust the notion of one god, the powerful fatherfigure of monotheism, the figure to whom weowe absolute obedience who has authority over us.

RICHARD RORTY [continued]: And this is just an idea that we would be better off without.

NARRATOR: To compare Popper's and Kuhn's positions,consider how they look at the shift from IsaacNewton's theory of gravity to Albert Einstein's.In Newton's theory, gravity is causedby attraction between bodies.The planets stay in orbit around the sundue to the balance between the pull of gravityand their own momentum.

NARRATOR [continued]: In Einstein's theory, large massescurve the space around them.Planets move through the curvature of spacearound the sun.Attraction is not a factor.How should we look at these two theories?Popper contends that gravity is a fundamental feature

NARRATOR [continued]: of reality.Newton's theory probed it deeply,but Einstein's theory probed it even more deeplyand gave us a truer account of the universe.Kuhn, by contrast, questions whether wecan think in terms of fundamental reality.For him, both theories are simplyparadigms, explanations that were widely

NARRATOR [continued]: accepted by scientists in different eras.Indeed, Kuhn takes exception to the whole realist effortto base the search for truth on a belief in objective reality.

THOMAS KUHN: There is, I think, no theory-independent wayto reconstruct phrases like "really there."The notion of a match between the ontology of a theoryand its real counterpart in naturenow seems to be elusive in principle.

NARRATOR: Kuhn's view that all theories or paradigms dependon consensus within a community and that paradigms come and gohas often been criticized as relativism.In relativism, all theories are tied to a point of view,and there are no independent standards for truth.Kuhn vehemently denied being a relativist

NARRATOR [continued]: and defended conventional standardsfor evaluating scientific theories.

IAN HACKING: He always insisted that, first of all,he accepted the standard moral values-- I call them moraldeliberately-- where you prefer theories which are simple,which are not ad hoc, don't just try to fit things in,which honor the largest amount of data which is available,

IAN HACKING [continued]: which provide more predictions and explanations than wereavailable before standard things out of a sciencetextbook of 200 years, of a science methodologytextbook of 200 years.I have all those values.They just don't determine what happens

IAN HACKING [continued]: in the course of actual scientific research,and he said that to be a relativistwould be to dismiss all our usual markers of truthand success in science.

MAN: This site has a lot of clay in it, Don.

NARRATOR: Both correspondence and coherence theories of truthhave been criticized for their abstractness and dependenceon arguments.Often, the truth seems to depend moreon what works in the real world.

PAUL CHURCHLAND: The way in which we can judge our beliefsis by testing them in experience,by seeing if they can sustain an industry,whether they can predict the outcomes of experiments,whether they can provide tools thatwill keep an economy going.

NARRATOR: A theory about truth called pragmatism arosein late 19th century America.In his 1907 book, Pragmatism-- A NewName for Some Old Ways of Thinking,William James contrasts pragmatistswith what he calls intellectualists.

WILLIAM JAMES: Truth, as any dictionary will tell you,is a property of certain of our ideas.It means their agreement as falsitymeans their disagreement with reality.Pragmatists and intellectualists both accept this definitionas a matter of course.They begin to quarrel only after the question is raisedas to what they precisely be meant by the term agreement,

WILLIAM JAMES [continued]: and what by the term reality.The great assumption of the intellectualistsis that truth means, essentially,an inert static relation.You've got your true idea of anything.There's an end of the matter.Pragmatism, on the other hand, asks its usual question--grant an idea or belief to be true, it says,

WILLIAM JAMES [continued]: what concrete difference will itsbeing true make in anyone's actual life?What is the truth's cash value in experiential terms?The moment pragmatism asks this question, it sees the answer.True ideas are those that we could assimilate, validate,corroborate, and verify.

WILLIAM JAMES [continued]: False ideas are those that we cannot.The truth of an idea is not a stagnant propertyinherent in it.Truth happens to an idea.It becomes true, is made true by events.

NARRATOR: Pragmatism was influencedby Charles Darwin's ideas about the survival of the fittest.In contrast to theories of truth based on abstract ideas,pragmatism can be seen as grounded in basic biology.

PAUL CHURCHLAND: Early creatures in evolutionary historyhad the problem also of representingthe way the world is, but they weren'tinterested in mirroring the abstract structureof the world.They were interested in blasting through breakfast to lunchand getting their genes into the next generation.And so pragmatic criteria tended to steer both the nature

PAUL CHURCHLAND [continued]: of their biological organization and the beliefs and conceptsthat they embraced in the course of a lifetime.I think we're still in the same position.

STEPHEN TOULMIN: And I think this is where pragmatismeventually takes you.My own view is that theorizing isitself another form of practice and that whatmakes theorizing intelligible is that we can understand itas a practice. [Stephen Toulmin, University of SouthernCalifornia] In the course of some practical activity,whether it's clinical medicine or physical astronomy

STEPHEN TOULMIN [continued]: or whatever it is, we appeal to theory,but what makes this appeal to theoryOK is what it does for us in relation to our practice.

NARRATOR: In science, pragmatism is sometimescalled instrumentalism since it sees theoriesas instruments or tools.That truthfulness of a theory dependson how well it generates predictionsthat produce results.

ARTHUR FINE: Now instrumentalism holds very roughlythat what we aim for in our scientific theoriesis not the truth about an external world, whichis the realist position, but whatwe aim for in our scientific theoriesis something like utility, which wouldbe the instrumentalist word.I like the word reliability better.

ARTHUR FINE [continued]: So what we're aiming for are theories or accountsor pictures or models of the world that are reliable.Reliable for what?Well, for whatever purposes we might want to put them to use.

NARRATOR: Sometimes a theory may show its pragmatic valueby producing results outside of science.Other times, it may do so by improving practicewithin science.

WV QUINE: You introduce a concept.You turn it into science.A new definition, new principles coming with it.On what basis do you do so?Well, you find that, if true, if the experiment's beared out,it's going to simplify this theory.It's going to draw two separate pressure

WV QUINE [continued]: theories closer together.It's going to make it possible to do some moreexperiments of a decisive kind.It's instrumental for that.

ARTHUR FINE: So our theory should be reliablefor crudely instrumental purposes,for building bridges and airplanesand making exquisite video equipment.But our theory should also be reliable as reflective toolsfor exploring some aspects of the world around us

ARTHUR FINE [continued]: that we haven't yet come to terms withand, perhaps, even yet begun to conceptualize.

NARRATOR: Perhaps the sharpest debatebetween realist and instrumentalistviews of science has come in relation to quantum mechanics.This modern offshoot of physics concernsatomic and subatomic particles and has triggered breakthroughsin fields such as atomic energy, lasers, and electricity.Since atoms are too small to observe, theories about them

NARRATOR [continued]: are, by necessity, highly speculative.Experiments in the early 20th centurysuggested that it is not even possible to say if electronsare particles or waves.

HILARY PUTNAM: When you run beyond the limits of evenextended observability, you run precisely the casewhere you really have great difficultyin knowing what to say about questions like real or not.

NARRATOR: One group of physicistsheaded by Niels Bohr adopted whatbecame known as the Copenhagen Interpretation.

ARTHUR FINE: The dominant view of peoplewho came to practice in the quantum theorywas an instrumentalist view.That is to say they thought the theory did not give youa picture of the world, but it gave a calculational tool.

HILARY PUTNAM: We accept it not because we understand it,because we don't, but because it leads to predictionsto more decimal places than we everimagined a scientific theory could lead to true predictionsand continues to surprise us with how immensely accurateit is, even though as I say, we understand it only

HILARY PUTNAM [continued]: in the sense of knowing how to manipulate it mathematically.

NARRATOR: In the famous double slit experiment, for example,you shoot electrons through two slits onto a collecting screen.If electrons behaved like larger objects, such as bullets,you would expect them to strike the screen in the patternof the slits, but they don't.

ARTHUR FINE: And the quantum theorygives you a very accurate, I mean,uncannily accurate prediction for the pattern that you'regoing to get on the collecting screen.It's going to be a characteristically wavypattern.

NARRATOR: Even more startling, quantum theorycontends that there is no way to determinethe path any given electron takes to reach the screen.

ARTHUR FINE: So what you can say on the basis of the quantumtheory is the particle leaves the source,and it arrives on the detecting screen,but you cannot say how it gets between the sourceand the detecting screen.You cannot even say-- and this is what's quite remarkable--that it goes through one slit or the other.

NARRATOR: Previously, scientists hadassumed that Newton's mechanics correctly described the motionsand interactions of all bodies.But now Bohr and others argued that Newton's laws did notapply at the quantum level.

ARTHUR FINE: The kind of questionthat you can ask on the basis of classical physics,although of a moving body, is you can say,where is it at a given time?How fast is it moving?And in what direction is it moving?So you can ascribe to a moving bodyboth position and the velocity, velocity being speed

ARTHUR FINE [continued]: and direction of motion.According to the quantum theory, as it was generally understood,one could not do the same thing for a moving quantum object,for an atom or a molecule or a subatomic particleof some kind.

NARRATOR: In quantum theory, you canmeasure the position or velocity of a particle,but not both at the same time.And so Bohr argued that we should give uptrying to say what might really exist at the quantum leveland simply use quantum theory as a calculating tool.

HILARY PUTNAM: I think Bohr's council was partlya council of despair that he was, oh,we are never going to understand quantum mechanicsor that it's intrinsically beyond the powerof the human mind to understand it in the categories thatare the only categories he thoughtwe'd have available to us-- space, time, and causality.

NARRATOR: The realist side of the debatewas championed by Albert Einstein, the fatherof relativity theory, and the most eminent scientistof the era.

ARTHUR FINE: Einstein had a sensethat if you began to take a very pragmatic attitudetowards physics, Einstein had the sensethat physics would degenerate.For Einstein, physics was a kind ofgrand intellectual adventure.For Einstein, physics was discovering the finer aspects,

ARTHUR FINE [continued]: the deeper structure of reality.Sometimes Einstein would put it in religious or quasi religiousterms.It's as though he thought that God created the universein a way that made it difficult for human beings to comprehend,but not impossible.He had this wonderful phrase, the Lord

ARTHUR FINE [continued]: is subtle but not malicious.And what he meant was exactly that the lord makesthe features of the universe difficult for us to find,but he wouldn't lead us to seek those featuresunless we could find them.

NARRATOR: Although the arguments are very complex,the alternative Einstein proposedwas that if quantum theory broke downcategories such as space and time,we should think of new and deeper categories.

ARTHUR FINE: If it's really true that position and momentumfragment in this way so that you can have one or the otherbut never both at the same time, then in Einstein's eyes,this provided grounds for saying,let's look for a different set of concepts.Let's try to understand the world conceptuallyon the basis of something new.

NARRATOR: Most importantly for Einstein,whatever new concepts we developed,they should attempt to describe the underlyingstructure of the universe.

ARTHUR FINE: And so Einstein maintained this faiththat that's really in the end what physics was about.Physics wasn't about tinkering.Physics wasn't about experimental prediction.Physics was finding out the most exquisite, deeply hiddenfeatures of the universe.And this is a typical kind of realist orientation.One of the things that always separates the realist

ARTHUR FINE [continued]: from anti-realists of various kindsand certainly from the pragmatistor the instrumentalist is the realistalways wants to probe deeper and deeper and deeperto find out the more hidden and the more exquisite features.The instrumentalist wants to understandwhat needs to be understood for certain kinds of tasks,

ARTHUR FINE [continued]: but then is content to say, let's leave it at that,unless circumstances force us to push forward.

NARRATOR: Einstein spent the last 20 years of his lifein an unsuccessful attempt to develop a unified fieldtheory that would provide a realist explanation for quantumphenomena.For many years, Bohr was seen as having won the debate,but in recent years, the balance has shifted somewhat back.

DAVID CHALMERS: I think there's a growing perception.Although Einstein wasn't right about everythingabout quantum mechanics, in the debate with Bohr,he was at least on to the existence of a real puzzleand a real problem.And now, in fact, a lot of interesting workin quantum mechanics over the last five or 10 yearshas been the development of new and alternativeinterpretations, detailed interpretationsof quantum mechanics.

NARRATOR: What is truth?In both philosophy and science, various theorieshave attempted to provide an answer.Each seems to contribute a vital perspective,but do any cover the whole picture?

STEPHEN TOULMIN: I rather admire the thingsthat Richard Rorty has said about the importancein philosophy of not getting hung upon big words with capital letters,big words with upper case letters,Truth with a capital T, Reality with a capital R,

STEPHEN TOULMIN [continued]: Proof with a capital P, and so on,but realize that in ordinary life, whatwe're concerned with is truths in the plural with a small T.

HILARY PUTNAM: When you attempt to find one characterizationof truth that covers every kind of truths,it seems to me now doomed to failure.It's like the attempt to find one accountof the scientific method, which coversevery single kind of scientific situation, every single kindof scientific hypothesis.It's a tendency in philosophy to look

HILARY PUTNAM [continued]: for the generalization that covers all the cases,and we always lose.But we can't resist trying.[MUSIC PLAYING]