p160 antirealismclassroomversion
TRANSCRIPT
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Goal of science:develop good
theories of the world.
Goal of science:develop good
theories of the world.
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Goal of science:develop good
theories of the world.
Goal of science:develop good
theories of the world.What makes a theory good?
What makes a theory good?
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Science aims for literally true
theories.
Science aims for literally true
theories.
Science aims for empirically adequate
theories.
Science aims for empirically adequate
theories.
Scientific Realism:Scientific Realism:
Scientific Antirealism:
Scientific Antirealism:
Realism vs. AntirealismRealism vs. Antirealism
Empirically adequate = Empirically adequate =
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Making true claims about all the observables
Making true claims about all the observables
(but claims about unobservables might
be false)
(but claims about unobservables might
be false)
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Is an aim of science literally true theories?
Is an aim of science literally true theories?
Grover Maxwell: YES!
Grover Maxwell: YES!
(Jones’ theory of disease)
(Jones’ theory of disease)
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Disease spread by:• bodily contact with sick person• contact with items handled by sick person
Disease spread by:• bodily contact with sick person• contact with items handled by sick person
Observations:Observations:
Another phenomenon with same pattern of spread: LICE
Another phenomenon with same pattern of spread: LICE
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Disease spread by “crobes” transmitted in the same ways lice
are transmitted.
Disease spread by “crobes” transmitted in the same ways lice
are transmitted.• Crobes too small to be seen.
• Halt spread of disease by halting spread of crobes.
• Crobes too small to be seen.
• Halt spread of disease by halting spread of crobes.
Jones’ conjectureJones’ conjecture
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• Predicts who will get sick.• Predicts who will get sick.• Suggests ways to stop spread of disease (“disinfection”).
• Suggests ways to stop spread of disease (“disinfection”).
Theory works!Theory works!
Should we believe in crobes?Should we believe in crobes?
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Maxwell: No principled line we could draw between
observable and theoretical entities.
Maxwell: No principled line we could draw between
observable and theoretical entities.Nothing disreputable about
crobes!
Nothing disreputable about
crobes!
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NOT a problem of observable vs.
theoretical entities.
NOT a problem of observable vs.
theoretical entities.
Problems with MaxwellProblems with Maxwell
Rather, observable vs. unobservable.
Rather, observable vs. unobservable.
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Rather, no data to determine whether they exist or not.
Rather, no data to determine whether they exist or not.
Antirealist doesn’t need to say
unobservable entities don’t exist.
Antirealist doesn’t need to say
unobservable entities don’t exist.
Problems with MaxwellProblems with Maxwell
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Argument from success of theory to
existence of crobes is logically flawed!
Argument from success of theory to
existence of crobes is logically flawed!
Problems with MaxwellProblems with Maxwell
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So, crobes exist!
So, crobes exist!
1. If there are crobes, and if crobes cause disease, then taking steps X to stop their
spread will reduce the incidence of disease.
1. If there are crobes, and if crobes cause disease, then taking steps X to stop their
spread will reduce the incidence of disease.2. Taking steps X is
followed by a reduction in the incidence of
disease.
2. Taking steps X is followed by a reduction
in the incidence of disease.
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So, my battery is dead.
So, my battery is dead.
1. If my battery is dead, then my car
won’t start.
1. If my battery is dead, then my car
won’t start.2. My car won’t
start.2. My car won’t
start.
Bad logic! (“Affirming the consequent”)
Bad logic! (“Affirming the consequent”)
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Can only get empirical evidence about
observables, not unobservables.
Can only get empirical evidence about
observables, not unobservables.
van Fraassen’s antirealism:Constructive empiricism
van Fraassen’s antirealism:Constructive empiricism
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van Fraassen’s antirealism:Constructive empiricism
van Fraassen’s antirealism:Constructive empiricismIf I accept a theory, I
believe the claims it makes about
observables are true.
If I accept a theory, I believe the claims it
makes about observables are true.Claims theory makes about unobservables
could be false.
Claims theory makes about unobservables
could be false.
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Detectable with unaided
senses.
Detectable with unaided
senses.
Observable:
Observable:
• some observables may not have been observed.• some things would be observable if they existed.
• some observables may not have been observed.• some things would be observable if they existed.
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Not detectable with unaided
senses.
Not detectable with unaided
senses.
Why aren’t crobes
observable?
Why aren’t crobes
observable?
What you see: consequences of arrangement of
instrument + sample
What you see: consequences of arrangement of
instrument + sample
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Duhem:Observations with
instruments assume theory of the
measuring device
Duhem:Observations with
instruments assume theory of the
measuring devicearrangement of instrument +
sample
arrangement of instrument +
sample
observables
(seen through
lens)
observables
(seen through
lens)
unobservables (causing what
is seen)
unobservables (causing what
is seen)
??
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Accepting a theory
Accepting a theoryRealist:
I believe all the claims the theory makes are true.Antirealist:I believe the claims the theory makes makes about observables are true.
Realist:I believe all the claims the theory makes are true.Antirealist:I believe the claims the theory makes makes about observables are true.
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Hacking’s middle position:
Hacking’s middle position:
“Entity Realism”: I believe all the entities the theory identifies really exist,
but some of the claims the theory makes about them may be false.
“Entity Realism”: I believe all the entities the theory identifies really exist,
but some of the claims the theory makes about them may be false.
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Hacking:Microscopes tell us
something is there, but may not show us just
what that something is like.
Hacking:Microscopes tell us
something is there, but may not show us just
what that something is like.
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What a microscope gives:
Map of the interaction between
specimen and imaging radiation.
What a microscope gives:
Map of the interaction between
specimen and imaging radiation.
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Features vs. artefacts:Features vs. artefacts:Features observed from sample using different types of radiation
Features observed from sample using different types of radiation due to real
features of sample
due to real features of sampleFeatures observed from one
type of radiation different using many different samples
Features observed from one type of radiation different using many different samples due to
instrumentdue to instrument
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Entity Realism: Entity Realism: We can believe that what we see with the microscope is caused by really existing entities.
We can believe that what we see with the microscope is caused by really existing entities.Why? Because we can manipulate those entities!Why? Because we can manipulate those entities!
Chiharas’ mitesChiharas’ mites
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Hard-core antirealist:Hard-core antirealist:• Claims the mites
exists (they’re observable).• Can’t know whether the mites have legs or not!• Can’t explain changes in movement in terms of leg-removal!
• Claims the mites exists (they’re observable).• Can’t know whether the mites have legs or not!• Can’t explain changes in movement in terms of leg-removal!
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What counts as a good explanation
anyway?
What counts as a good explanation
anyway?
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