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36 Cards in this Set

  • Front
  • Back
Doctrines of Logical Positivism (2)
Verification Theory of Meaning

Analytic/Synthetic Distinction
Verification Theory of Meaning
Theory states that a non-analytic statement is only meaningful if it is verifiable/testable by sense experience and observation.
Vagueness of the Verification Theory of Meaning
Does verify mean that we are able to confirm in-practice or confirm in-principle?

How much verification is needed? Is a theory 'more' confirmed with more evidence?
Attractions of the Verification Theory of Meaning
-For non-understood claims, the philosopher could be asked what observations they used to make the claim.
-Science seems to make statements that are tied very closely to sense experience.
-Our ability to understand major portions of language involve having had appropriate sense experience.
-'Problem of the external world' does not matter because 1. the real world is only an obervation of our mental impression and we can never make an observation of the real world and 2. we can directly observe the real world exists if it is just claims about the stability of our sensations.
Unattractive elements of the Verification Theory of Meaning
Imprecise meaning of 'Verifiable' - in practice - w/in our ability to confirm now - in principle - limited by our current knowledge and technology but conceptually can verify.
Does verify mean to know with certainty or to have some evidence for/against.
Analytic Statement
Statement that is true/false just in the virtue of meaning alone. Does not depend on how the world is.

'All bachelors are unmarried'
Synthetic Statement
The truth of the claim depends upon how the world is and they are substantively about the world.

'All bachelors are happy.'
'The president of the US is George Bush.'
A Priori
A proposition whose justification does not rely upon experience. Observation not required.

again 'all bachelors are unmarried'
A Posteriori
A proposition whose justification does rely upon experience. Observation required.
Analytic, A Priori knowledge
Once meaning understood dont need sense experience to prove.

To know an analytic statement to be true or false, a priori knowledge is used rather than observation to confirm. It is non-mysterious in this way.
Synthetic, A Priori knowledge
Deeply mysterious...statement makes claim about the world but which can be known to be true just by reason.

'Triangles have angles that sum to 180 degrees'

Logical positivist say there are no synthetic a priori. - because of einstein relativity triangle does not equal 180
Quine-Duhem thesis
Quine against verification theory of meaning - A single scientific theory/statement cannot be tested in isolation; a test of one theory always depends on other theories and hypotheses.

A single sentence does not generally have observational consequences. 'A tree is in front of me'.
It might be too dark, my eyesight might be bad.

We test only groups of sentences/hypotheses.
Quine against analytic/synthetic
If observational consequence of statement does not happen, logic does not tell us where the problem was. If don't see tree, can blame eyesight vs. tree not really there.

This logic was only put toward analytic but quine said it applies to synthetic as well. Can place blame for false prediction anywhere.

A priori knowledge is fallible..we might still be wrong about it.
If the premises are true then the conclusion has to be true.

All men are mortal.
Socrates is a man.
Socrates is mortal.
A non-valid argument. A generalization from previous observations. Does not guarantee conclusion to be true.

Student1 is from California
Student2 is from California
StudentN is from California

All students are from California
Enumerative Induction
From a number of observed cases, you arrive at a prediction about all cases...

Swan1 - White
Swan2 - White
Swan1000 - White
All Swans are White...
Projection Induction
From a number of observed cases, you arrive at a prediction about the NEXT case...

Swan1 - White
Swan2 - White
Swan1000 - White
Swan1001 - White...
Abductive (explanatory) Induction/Inference
Conclusion with the best explanation of observations and data is true.

1. Unusually high amounts of rare element in soil layer 65 Myo.
2. Rare element is fount in much hier concentration in meteor.
Concl. Meteor hit the earth around 65 Mya.
Hypotheses in science are confirmed (weak confirm - some evidence) when their logical consequences turn out to be true.

Seems to work within scientific theory but when stated in simple logical terms, falls apart.

Any theory T deductively implies T or S (S is any sentence at all.)
If S true then T is true...
Hypothetical-Deductivism Example
If its raining, car is getting wet.
It is raining
Car is getting wet.

Doesnt mean that it is raining. Could be sprinklers.
An object is GRUE if and only if it was first observed before 2010 AD and is green, or if it was NOT first observed before 2010 AD and is blue.
An object is bleen if and only if it was first observed before 2010 AD and is blue, or if it was NOT first observed before 2010 AD and is green.
Nelson Goodman's "Grue" Problem
The problem is to explain why an emerald observed after 2010 AD is not grue.

1-Definition of grue is disjunct.
But should be able to accept 'grue is first observed before 2010 AD and bleen otherwise'
2-'x' is grue is not solely a predicate of 'x -green' but green and time as well.
definition of green doesnt require time but grue does...
Curve fitting problem
Have a finite amount of data. Usually hypothesize that the unknown/unobserved point is connected in the most simple pattern possible. most simple - choose green - is green really simpler?

Why does it have to be simple?
What justifies that choice?

Fitting strange function to the unobserved point is like preferring grue over green.
the Demarcation Problem
Delineating the difference between science and psudo-science, science and non-science, science and religion.
How does Popper's project differ from the logical positivists?
Popper's aim is to delineate the the demarcation problem. LPs want to give an account of what sentences count as meaningful.
Popper's view of induction
Believes induction is irrational since unjustified. No matter how many emeralds seen doesn't justify belief that all are green. Weak but not conclusive evidence.

Single NON green emeralds deductively shows that the induction is false.

Falsification rather than verification is important in science since it requires no irrational induction but deduction only.
How does scientific method work for Popper?
Scientist do not use induction but rather make 'BOLD CONJECTURES' to reach hypotheses...they make predictions such that if they are false the theory is refuted. If there is no risk of being refuted, it is not scientific.

If scientists refute their theory, they must make a new bold conjecture. If not refuted, does not justify in belief that theory is true or probably true (That's induction!).

Most we can say is theory has not yet been refuted.
BOLD Conjecture
To make a hypothesis that makes predictions such that if they are false the theory is refuted.
Problems w/ Popper's views
-Scientist can save 'favorite' theory from falsification by blaming incorrect prediction on an auxilary hypothesis.

-Cannot completely be certain about the accuracy of observations...therefore cannot be sure any prediction was false.
P says acceptance of observation is decision or convention...why then can we decide to accept theory...?

-Further scientific progress might lead to theory becoming falsifiable. Cannot dismiss anything as unfalsifiable.

-Theories do not predict certain observation will not happen...only that they are very unlikely. When obs does occur is this falsification is it's only unlikely? Again "decision"

-When is it better to choose a hypothesis that has been subjected to attempts of falsificati and pass..than to a hypo that has never been.
Descriptive vs. Prescriptive Philosophy of science
Descriptive - what scientists are doing now.

Prescriptive - what scientists should have been doing.

Popper gives the second.
Duhem Ans 1 - Reductio ad absurdum
-Make assumption
-show that contradiction follows deductively from that assumption.
--we then know assumption is false.

Scientist agree there is contradiction but which auxilary hypo is wrong?
Duhiem Ans 2 - List all possible hypotheses
List all possible hypotheses then eliminate them 1x1 by experimental contradiction.

prob1 - did we list all hypotheses?
Crucial Experiment
A irrefutable procedure for transforming one of the two hypotheses into a demonstrated truth.
Duhem ans 3 - the Newtonian/Inductive method
Build up hypotheses from observations and induction in the right way so that we can be confident that the theory is correct.

newton started with keplers laws which were based on brahes observations
Duhem's conclusion
We do not build theory out of experiment. Once theory is born we measure it against experiment. theory can choose any path as long as it avoids logical contradiction.