Updated: 03 March 2000
The Realist Picture
Start with observations
Explain by reference to the
Inference to the best
mountains on the moon
atoms via Brownian motion
Thomson - electrons
Confirm by successful novel
The theory provides a literally true (or truth-like) account of the
underlying mechanisms in the world
Real realism –
truth as correspondence
reject reconstruals of truth (eg Peirce)
Aim of science is the truth-related aim of
having theories of ever greater verisimilitude.
Problems: meaning of
Observational success of science
Science uses IBE
Use IBE in your theory of science
What is it about today’s theories that enables them to give better
theories are more approximately true
advanced in contexts of Kuhnian scepticism
Limited epistemic skepticism
How do you know about electrons ?
Experience is the source of all knowledge, don’t have experience of
Limited - knowledge of observable states
Limited semantic skepticism
What do you mean?
Cannot give verbal definitions or ostensive examples for theoretical
No more meaning than Hodge’s uninterpreted symbols
theories are just
T-terms lack meaning
T-terms have meaning and T sentences have truth-values. But utterly unknowable.
van Fraassen: The Scientific
aim of science: empirical adequacy
scientist does not believe a theory
scientist “accepts” a theory
= believing in its
Objections to Explanatory Realism
Nothing to explain.
Theories picked for predictive power. That is why they are predictively
- question begging - instrumentalist challenges its use as an epistemic
tool in science
- explanation not linked to truth
no satisfactory account of verisimilitude (Laudan
: Science and Values)
historical record is dubious (Laudan)
Underdetermination of theory by data.
IBE ok from observables to
Crucial to distinquish between:
O and T
O and non-O
i) Schlick : O
experience - sense data
ii) Carnap - matter of degree
accurately, confidently decide
iii) van Fraassen -
biological basis - what humans could (if suitably located) settle by using
aim of science goes beyond that of empirical adequacy
Inference to the Best Explanation
Argues for TV on the grounds that it provides best explanation of
increasing observational successes of science
Seeks to justify positing atoms, electrons etc
Miller “book length argument for realism”
Underdetermination of theory by data
Underdetermination by the actual available data
Threat to IBE ?
- wait and see
Undetermination of theory by all
actual and possible data
For any theory T1 there is a theory T2 :
T1 and T2 are incompatible.
T1 and T2 are empirically equivalent
T1 and T2 are fare equally well on
all other epistemic principles of theory choice.
Strong UTD - applies to all theories
Weak - applies to some theories
Observationally omniscient God
What hope for realism?