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Presentation about the Paper "Why are Good Theories Good.Reflections on epistemic values, confirmation, and formal epistemology "
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WHY ARE GOOD THEORIES GOOD ?
REFLECTIONS ON EPISTEMIC VALUES , CONFIRMATION, AND FORMAL EPISTEMOLOGY
Sinu G S
Student MICS
Selected Topics in Artificial Intelligence
University of Luxembourg
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THEME OF PAPER
This paper discusses about
Comparison of Theory of Confirmation and Theory of Verisimilitude or Truthlikeness.
Connection between Logic of Confirmation with Logic of Acceptability
Connection of Confirmation Theory with Naturalism,Intertheoretic Reduction and Explanation.
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AGENDA OF PRESENTATION
Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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INTRODUCTION
Epistemology Theory of Knowledge and justified belief
Theories and Evidence Theory Real World Data(Evidence) Predictions
Confirmation
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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APPROACHES OF CONFIRMATION
Inductive Logic
Induction proceeds from the specific case to the general case: “probable inference”
All swans we have seen have been white; therefore all swans are white.
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INDUCTIVE LOGIC METHOD
Initial observation
New observations
Prediction
hypothesis
Do new observations match
predictions?
“Accepted truth”
suggestsgenerates experiments and data
NO, modify hypothesis
YES, confirm hypothesis
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APPROACHES OF CONFIRMATION
Deductive Logic
Deduction proceeds from the general case to the specific case: “certain inference”
For every action, there is an opposite and equal reaction. This rifle will recoil when it is fired.
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HYPOTHETIC-DEDUCTIVE LOGIC METHOD
Initial observation
New observations
Prediction A
hypothesis
Do new observations match
predictions?“Accepted
truth”
suggests
NO, falsify hypothesis
YES, repeat attempts to falsify
hypothesis hypothesis hypothesis
Prediction B Prediction CPrediction D
Multiple failed falsifications
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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PROBLEMS OF CONFIRMATION
What makes an observation count as evidence ?
This piece of copper conducts electricity This confirms (increases the credibility of)
Hypothesis “All pieces of copper conduct electricity”
Law Like Hypothesis
This man performs scientific experiments This confirms(increases the plausibility) of
idea all man perform scientific experiments Accidental Hypothesis
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PROBLEMS OF CONFIRMATION
How do observations confirm a scientific theory ? You can know only what you observed and you
have never observed a “Law of Nature” Russell’s Chicken Story
Moral of the story: You cannot always induce the truth from past experience!
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PROBLEMS OF CONFIRMATION
Raven’s Paradox
P1 : All ravens are black. P2 : Everything that is not black is not a
raven
E1 : This raven, is black. E2 : This red (and thus not black) thing is an
apple (and thus not a raven).
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PROBLEMS OF CONFIRMATION
Moral of Raven’s Paradox Theory of Confirmation
“With in certain limits,what is the true of evidence statements is true of the whole ‘universe of discourse’ Evidences may depends on Context.
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PROBLEMS OF CONFIRMATION
A logical consequence of any theory T is T or S.
“Earth is center of solar system or I am 23 years old”
I am actually 23 years old. This means Earth is center of Solar System
(Logical Sequence of I am 23 years old ) is confirmed by observing ‘ I am 23 years old’
Can nature of solar system be confirmed by my age ?
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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HUBER’S THEORY OF CONFIRMATION
Problem of Theory of Theory Assessment
How we compare and evaluate theories in the light of available evidence?
Given Hypothesis or Theory H Set of data,the Evidence E Some Background information B
How good is H given B ? What is the value of H in view of E and B ?
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HUBER’S THEORY OF CONFIRMATION
Qualitative Theory of Hypothetico-Deductivism
(H&B) E Aims at informative theories
Quantitative Theory of probablistic inductive logic
P(H|E&B)>=r , r (.5,1) Aims at plausible or true theories
Increasing Function of Logical Strength of Theory
Decreasing Function of Logical Strength of Theory
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HUBER’S THEORY OF CONFIRMATION
Conflicting Concepts of Confirmation Informativeness If E confirms H and H0 logically implies H, then
E confirms H0 . E |∼ H, H0 H ⇒ E |∼ H0.
Plausibility If E confirms H and H logically implies H0, then
E confirms H0. E |∼ H, H H0 ⇒ E |∼ H0
A good theory is true & informative
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HUBER’S THEORY OF CONFIRMATION
2 virtues a good theory
Truth (or ‘plausibility’) Strength (or ‘informativeness’)
f (H, E, B) Epistemic value of Hypothesis
If E entails H → H’, then f (H, E) ≤ f (H’, E) If ¬ E entails H’ → H, then f (H, E) ≤ f (H’, E) f (H, E) = p (H, E) + p (¬H,¬E)
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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CONFIRMATION AND TRUTHLIKENESS
Knowledge Justified True Belief
Belief An Idea Some one has about the world
True Corresponds with facts Justified Not just a coincidence
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CONFIRMATION AND TRUTHLIKENESS
Karl Popper’s view Belief
What if every one lost all their beliefs about engineering
Justified Circular Argument
Why A ? Because B Why B ? Because A
Criticise Beliefs,Don’t Justify them Knowledge is useful truth.
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CONFIRMATION AND TRUTHLIKENESS
Acceptable theories
Not Only High degree of confirmation But Also Capacity of explaining or predicting the
empirical evidence
Epistemic value of a theory depends on two factors
Coherence or Similarity between H and E How Informative our Empirical Evidence is ?
Vs (H, E) = [p (H&E) /p (HvE)] [1/p (E)] = p (H, E) /p (HvE)
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CONFIRMATION AND TRUTHLIKENESS
H is more verisimilar than H’
High Similarity High Informative
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CONFIRMATION AND TRUTHLIKENESS
Properties of Empirical Verisimilitude
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CONFIRMATION AND TRUTHLIKENESS
Properties of Empirical Verisimilitude
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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MANY SENSES OF CONFIRMATION
Acceptance of Theory H can be ‘acceptable’ in the sense that the
community allows that individual scientists accept H
H can be ‘acceptable’ in the sense that the community commands its members to accept it
What makes theory so good that it is legitimate to accept it ?
What makes theory so good that it is compulsory to accept it ?
Mostly Confirmed
Best one confirmed
Alternative Theorems
Certified Knowledge
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MANY SENSES OF CONFIRMATION
X ,the set of all possible mutually exclusive sets of consequences that the choice of a demarcation level β will have for scientist i, then,the optimal choice for that scientist will correspond to:
pi(x,b) is obviously the probability with which i judges that the choice of b will lead to consequences x,
ui(x) is the utility that i would experiment under x.
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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NATURALISM AND BAYESIAN TINKERING
Problem of theory evaluation’ is not a ‘philosophical’ problem, but a problem for the communities of flesh-and-bone scientists
Inter Theoretical Reduction increases epistemic values
Showing that a theory can be reducible to another increases the verisimilitude of both theories
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EXPLANATORINESS AND CONFIRMATION
A Theory H explains the facts F for the scientific community C if and only if F can be derived from H by C, and the members of C understand H, i.e., if H is ‘intelligible’ for them
Coeteris paribus, if X is easier to understand than Y, then p(Y) < p(X).
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Introduction Approaches of Confirmation Problems in Confirmation Huber’s Theory of Confirmation Confirmation and Truthlikeness Many Senses of Confirmation Naturalism and Bayesian Tinkering Belief Framework for modeling realistic
cognitive agents (Research Assistant Systems)
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CONCEPTUAL BELIEF FRAMEWORK (RESEARCH ASSISTANT SYSTEMS)
Background
Knowledge
Informativeness
Truthfulness
Acceptability
Hypothetico Deductive
Supportability
Inductive Supportability
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CONCEPTUAL BELIEF FRAMEWORK (RESEARCH ASSISTANT SYSTEMS)
Evidence
Informativeness
Truthfulness
Acceptability
Relativism
Totality(among set of enclosure)
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CONCEPTUAL BELIEF FRAMEWORK (RESEARCH ASSISTANT SYSTEMS)
Theory
Informativeness
Truthfulness
Acceptability Relativism
Supportability
Reducibility
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Queries and Suggestions
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