“the demarcation problem” (science and pseudo-science) case one: geocentrism (an earth-centered...

“The Demarcation Problem”(Science and pseudo-science)

Case one: Geocentrism (an earth-centered universe) vs. Case one: Geocentrism (an earth-centered universe) vs. Heliocentrism (a sun centered universe).Heliocentrism (a sun centered universe).

“The Demarcation Problem”Case one: Geocentrism (an earth-centered universe) vs. Heliocentrism Case one: Geocentrism (an earth-centered universe) vs. Heliocentrism

(a sun centered universe).(a sun centered universe).

Was geocentrism a Was geocentrism a scientificscientific hypothesis? hypothesis?How much of it was based on theology or appeals to ancient How much of it was based on theology or appeals to ancient

authorities (such as Aristotle), rather than on empirical authorities (such as Aristotle), rather than on empirical evidence and/or scientific reasoning?evidence and/or scientific reasoning?

Was heliocentrism a Was heliocentrism a scientificscientific hypothesis? hypothesis?

How could it be if it so obviously clashed with our How could it be if it so obviously clashed with our experience?experience?

Where is the wind? Why don’t we feel the earth’s motion?Where is the wind? Why don’t we feel the earth’s motion?

How does a telescope How does a telescope workwork? How do we know what Galileo ? How do we know what Galileo claimed to see (e.g., that Jupiter has moons) weren’t just claimed to see (e.g., that Jupiter has moons) weren’t just artifacts produced by his telescope? artifacts produced by his telescope?

Popper: “Falsifiability is the criterion”

Why reject verifiability?Why reject verifiability? By then (for reasons we will study shortly), By then (for reasons we will study shortly),

scientists and philosophers recognized that no scientists and philosophers recognized that no empirical theory could ever be proven.empirical theory could ever be proven.

This seemed to take any degree of certainty off the This seemed to take any degree of certainty off the tabletable

Moreover, according to Popper, “verifications” or Moreover, according to Popper, “verifications” or confirmations of a theory were, in many cases, all confirmations of a theory were, in many cases, all too easy to come by.too easy to come by.


By then (for reasons we will study shortly), By then (for reasons we will study shortly), scientists and philosophers recognized that no scientists and philosophers recognized that no empirical theory could ever be proven.empirical theory could ever be proven.

But Popper has logic on his side; for while no But Popper has logic on his side; for while no empirical theory can be proven, any (genuinely) empirical theory can be proven, any (genuinely) empirical theory can be empirical theory can be disprovendisproven and, at least in and, at least in principle, by just principle, by just oneone failed experiment or failed experiment or prediction.prediction.

The logic of confirmation vs. the logic of The logic of confirmation vs. the logic of falsificationfalsification

1.1. If If HH, then , then II

2.2. II

------------------------------------

HH

Logic of confirmation: Logic of confirmation:

Affirming the consequentAffirming the consequent

Deductively invalidDeductively invalid

1.1. If If HH, then , then II

2.2. Not Not II

------------------------------------

Not Not HH

Logic of falsificationLogic of falsification

Modus TollensModus Tollens

Deductively valid.Deductively valid.


In 1919, Popper compares 4 then popular and In 1919, Popper compares 4 then popular and much discussed theories: Relativity, Marxism, much discussed theories: Relativity, Marxism, Freudianism, and Adlerian PsychologyFreudianism, and Adlerian Psychology

Although the last three might contain important Although the last three might contain important truths or insights, and although they are said to truths or insights, and although they are said to enjoy extensive confirmations (supporting enjoy extensive confirmations (supporting observations and “experiments”), they turn out not observations and “experiments”), they turn out not to be scientific, according the Popper.to be scientific, according the Popper.

Although it was unclear at the time whether Although it was unclear at the time whether Einstein’s theory was true, it turns out to be Einstein’s theory was true, it turns out to be scientific on Popper’s view.scientific on Popper’s view.

Eddington’s experiment

Einstein’s theories predicted that light, like Einstein’s theories predicted that light, like material objects, is subject to the gravitational material objects, is subject to the gravitational “pull” of large objects“pull” of large objects

Hypothesis: light traveling from a star that is Hypothesis: light traveling from a star that is located “behind” the sun from the perspective of located “behind” the sun from the perspective of the Earth should bend as it passes the sunthe Earth should bend as it passes the sun

A bold hypothesis and one that would take years A bold hypothesis and one that would take years to carry out. Scientists had to wait for a solar to carry out. Scientists had to wait for a solar eclipse so that a star’s light would be visibleeclipse so that a star’s light would be visible


A reconstruction of what Eddington’s A reconstruction of what Eddington’s photographs demonstrated:photographs demonstrated:


A bold hypothesis and one that would take years A bold hypothesis and one that would take years to carry out. Scientists had to wait for a solar to carry out. Scientists had to wait for a solar eclipse so that a star’s light would be visibleeclipse so that a star’s light would be visible

But it was not its confirmation that struck Popper, But it was not its confirmation that struck Popper, but its but its falsifiability and boldnessfalsifiability and boldness: even before : even before Eddington’s experiment confirmed it, scientists Eddington’s experiment confirmed it, scientists knew what would, in principle, falsify the knew what would, in principle, falsify the hypothesis: namely, not observing the bending of hypothesis: namely, not observing the bending of the light traveling from the star toward Earth.the light traveling from the star toward Earth.

Falsifiability The criterion used to make these judgments and to The criterion used to make these judgments and to

be generalized: be generalized: Every genuinely scientific theory is a prohibition. Every genuinely scientific theory is a prohibition.

It forbids certain things to happen.It forbids certain things to happen. A theory that is not falsifiable (refutable) by any A theory that is not falsifiable (refutable) by any

conceivable event is not scientific.conceivable event is not scientific. Confirmations should Confirmations should only countonly count as supporting a as supporting a

theory if, like that of Relativity, they involve risky theory if, like that of Relativity, they involve risky and bold predictions.and bold predictions.

Falsifiability

Using the criterion to judge Marxism, Freudianism, and Using the criterion to judge Marxism, Freudianism, and Adlerian Psychology as examples of pseudo-scienceAdlerian Psychology as examples of pseudo-science

The problems with Freudian and Adlerian psycyhology:The problems with Freudian and Adlerian psycyhology: Each is compatible with every possible state of affairs.Each is compatible with every possible state of affairs. Each contains within it the means to explain conflicting Each contains within it the means to explain conflicting

results (e.g., whether an adult jumps into water to save a results (e.g., whether an adult jumps into water to save a drowning child or does not jump in – explanation “his or drowning child or does not jump in – explanation “his or her feelings of inadequacy”)her feelings of inadequacy”)

The “unconscious” of Freudian theory undercuts any The “unconscious” of Freudian theory undercuts any individual’s claim not to experience what Freud predicts individual’s claim not to experience what Freud predicts every male, or every female, experiences.every male, or every female, experiences.

Falsifiability

Marxism is rendered pseudo-scientific Marxism is rendered pseudo-scientific notnot because the original theory was not falsifiable.because the original theory was not falsifiable.

Marx and Engel’s claims about upcoming Marx and Engel’s claims about upcoming proletariat revolutions in capitalist societies were proletariat revolutions in capitalist societies were falsifiable, and in most cases, falsifiable, and in most cases, falsifiedfalsified..

But advocates of Marxism, in efforts to save the But advocates of Marxism, in efforts to save the theory from the falsifications, introduce theory from the falsifications, introduce Ad hocAd hoc hypotheses to save it.hypotheses to save it.

Ad hocAd hoc: From the Latin “for this purpose” (in this : From the Latin “for this purpose” (in this case, saving the theory…)case, saving the theory…)

Falsifiability

Ad hocAd hoc hypotheses and Marxism hypotheses and Marxism According to Marxism, each society has an According to Marxism, each society has an

“ideology” – a guiding set of ideas – that informs “ideology” – a guiding set of ideas – that informs its political and economic theories and institutionsits political and economic theories and institutions

Ideologies function to make the present political Ideologies function to make the present political and economic status quo look naturaland economic status quo look natural

So, workers (members of the proletariat) don’t So, workers (members of the proletariat) don’t recognize that capitalism exploits them and have recognize that capitalism exploits them and have to be taught to see through the ideology that their to be taught to see through the ideology that their economic system is a “meritocracy” with economic system is a “meritocracy” with unlimited possibilities to succeed.unlimited possibilities to succeed.

Falsifiability

When the many revolutions Marx and Engels When the many revolutions Marx and Engels predicted did not occur, later advocates of the predicted did not occur, later advocates of the theory pointed to the capitalist ideology as the theory pointed to the capitalist ideology as the culprit: workers couldn’t see through it and culprit: workers couldn’t see through it and recognize the truth. Hence, few revolutions.recognize the truth. Hence, few revolutions.

Note that this is a different kind of case from Note that this is a different kind of case from Freudian and Adlerian psychology: it’s not the Freudian and Adlerian psychology: it’s not the theory that is unfalsifiable, it’s the attitude of its theory that is unfalsifiable, it’s the attitude of its advocates and their willingness to propose advocates and their willingness to propose Ad hocAd hoc hypotheses to save it from falsificationhypotheses to save it from falsification

Things we will later consider…

The difference between a theory actually being The difference between a theory actually being unfalsifiable, by its nature or structure, and a theory’s unfalsifiable, by its nature or structure, and a theory’s advocates resorting to advocates resorting to ad hocad hoc hypotheses to save it. hypotheses to save it.

Isn’t it possible that a genuinely scientific theory will Isn’t it possible that a genuinely scientific theory will be confirmed repeatedly and no counter-examples be confirmed repeatedly and no counter-examples encountered?encountered?

The “in principle” caveat is important. “There is a The “in principle” caveat is important. “There is a little red school house on the dark side of Jupiter” is little red school house on the dark side of Jupiter” is sillysilly but but falsifiable in principle.falsifiable in principle.

How easy or straightforward is it to identify added How easy or straightforward is it to identify added hypotheses that ARE hypotheses that ARE ad hocad hoc, but added hypotheses , but added hypotheses that are NOT that are NOT ad hocad hoc (i.e., are defensible) (i.e., are defensible)

The Elegant Universe: previewThe Elegant Universe: preview

The two pillars of contemporary physics – The two pillars of contemporary physics – Relativity and Quantum mechanics – are (it Relativity and Quantum mechanics – are (it appears) incompatible.appears) incompatible.

Relativity theory concerns very large objects Relativity theory concerns very large objects (galaxies, starts, and the like)(galaxies, starts, and the like)

Quantum mechanics concerns very small objects Quantum mechanics concerns very small objects (atoms and subatomic particles)(atoms and subatomic particles)

They yield They yield different lawsdifferent laws.. Unification – “a theory of everything” is for many Unification – “a theory of everything” is for many

physicists the Holy Grail.physicists the Holy Grail.


String TheoryString Theory is seen by some physicists as is seen by some physicists as precisely the theory that will unite Relativity and precisely the theory that will unite Relativity and Quantum mechanics – it is (it will turn out to be) Quantum mechanics – it is (it will turn out to be) the theory of everything.the theory of everything.

It posits that everything, including Lederman’s It posits that everything, including Lederman’s quarks and leptons, is made of tiny, vibrating quarks and leptons, is made of tiny, vibrating strands of energy (they’re called strings)strands of energy (they’re called strings)

It has led to some strange predictions: parallel It has led to some strange predictions: parallel universes and 11 (yes, 11!) dimensions, among universes and 11 (yes, 11!) dimensions, among other things.other things.


Note how string theory, like particle physics, Note how string theory, like particle physics, quantum theory, the Greeks of Miletus, and quantum theory, the Greeks of Miletus, and Democritus, assumes there is one stuff out of which Democritus, assumes there is one stuff out of which everything is made.everything is made.

Strings are, by their nature, unobservable (and, Strings are, by their nature, unobservable (and, indeed, there are no technologies able to indirectly indeed, there are no technologies able to indirectly observe their effects – although some hope LHC observe their effects – although some hope LHC will help hewill help here)re)

Note the primary reasons physicists who are not Note the primary reasons physicists who are not String Theorists reject its status as “scientific”!String Theorists reject its status as “scientific”!

The Elegant Universe: previewThe Elegant Universe: preview Some of the players:Some of the players: Brian Greene, narrator and author of the book of Brian Greene, narrator and author of the book of

the same title. Professor of physics at Columbia the same title. Professor of physics at Columbia University. An advocate of String Theory…University. An advocate of String Theory…

Sheldon Glashow, Professor of Physics, Harvard, Sheldon Glashow, Professor of Physics, Harvard, Noble Prize in Physics, author of the “Credo” we Noble Prize in Physics, author of the “Credo” we read earlier. read earlier.

Steven Weinberg, Professor of Physics, University Steven Weinberg, Professor of Physics, University of Texas, Austin. Shared the Noble Prize with of Texas, Austin. Shared the Noble Prize with Glashow for their construction of “The Standard Glashow for their construction of “The Standard Model” in physics.Model” in physics.

“the demarcation problem” (science and pseudo-science) case one: geocentrism (an earth-centered...

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