Realism and Anti-realism

Our best scientific theories talk about unobservable entities

(e.g. atomic theory of matter)

They often have important technological applications

(e.g. laser technology)

Binoculars? Telescope?

High-powered microscope?

Many things that are observable, never actually get observed

Observable part

methaphysics

science

things which can be directly perceived by human beings

E.g.: fossils in palaeontology

Realists

Anti-realists

Philosophy of Science

Schools of Thought

7

We should interpret all scientific theories as attempted descriptions of reality

Realism

Scientific

realism

the aim of science is to provide a true description of the world

physical world exist independently of human thought and perception

This interpretation is inappropriate for theories that talk about unobservable entities and processes

vs

Anti-realism

(instrumentalism)

the aim of science...

...of the observable part of the world

Idealism

physical world is in some way dependent on the conscious activity of humans

Unobservable part

E.g.: electrons in physics

Entities beyond the reach of the observational powers of humans

Unobservable entities are merely convenient fictions, introduced by scientists in order to help predict observable phenomena

A Very Short Introduction to Philosophy of Science

REALISM AND ANTI-REALISM

Realists

Anti-realists

6

We already have substantial knowledge of unobservable reality

We cannot actually attain knowledge of the unobservable part - it's beyond human powers

The theory might be false, but so might any theory

Evaldas Jablonskis

Ljubljana, 09/01/2012

Two sorts of anti-realism

Beginning of XX century

Contemporary

Unobservable entities is not to be understood literally at all

The teories about unobservable entities are either true or false, but we will never know which

E.g. the talk about electrons is methaporical

Realists

Anti-realists

5

'No miracles' argument: many theories are empirically successful

There are many cases of theories that were empirically quite successful in their day, but now we know are false

(e.g. the theory that any burning object releases a substance called 'phlogiston', XVIII c.)

Unless we accept a theory, the empirical success of it is an unexplained mystery

Realists

Anti-realists

Modifications of

'No miracles' argument:

4

They reduce the number of historical counter-examples, but not to zero

the theories are true which allow us to predict new observational phenomena

the theories are approximately true, they may be not correct to every last detail

(e.g. the wave theory of light by Ch.Huygens, 1690)

Realists

Anti-realists

3

'Observable' is a vague concept (it has borderline cases) but since there are clear-cut cases, the concept is perfectly usable

How sophisticated can the instrumentation be, before we have a case of detecting rather than observing?

(e.g. the definition of a bald man)

E.g.: detecting electrons in a cloud chamber

Realists

Anti-realists

Observational data constitute the ultimate evidence for claims about unobservable entities

2

There are criteria for theory choice (probability, simplicity etc.) in addition to compatibility with the observational data

'Underdetermination' argument: there will always be a number of competing theories that can account for the observable

data equally well

Science often has difficulty finding even one theory that fits the data adequately

Realists

Anti-realists

1

'Underdetermination' argument is applied selectively: it should rule out the knowledge of much of the observable world

The argument is simply a sophisticated version of the problem of induction

Thank you!