Chapter 2 PowerPoint

advertisement

Theoretical Issues in Psychology

Philosophy of Science and

Philosophy of Mind for

Psychologists

B&LdeJ 1

Chapter 2

Kinds of explanations

• 3 kinds of explanations

• Reduction

• Levels of explanation

• Reasons and causes

• Explanatory pluralism

B&LdeJ 2

Explanation

Explanation is answering to a ‘why’ question.

Three kinds of explanations:

1) Nomological explanation (D-N model) answers

‘why’ by subsumption under a general law (‘covering law’):

• sciences.

2) Hermeneutic understanding (‘Verstehen’) answers

‘why’ by reconstructing context, explicating meaning and experience:

• humanities.

3) Functional explanation answers ‘why’ by finding the function (‘what is it for’); mechanistic explanation:

• biology ( engineering ); biological psychology.

B&LdeJ 3

Nomological explanation

law

1

…………law n condition

1

… condition n event (fact) explanans explanandum

• Subsuming an event (fact) under a general law.

• Or deducing an explanandum from an explanans.

• Prediction logically equals explanation.

Problem : doesn’t work for motives, reasons and actions.

B&LdeJ 4

Nomological explanation

Example:

L1: Frustration causes aggression

L2: Football supporters whose club lost are frustrated

C1: These supporters’ football club lost

----------------------------------------------------------

E: These football supporters are aggressive

B&LdeJ 5

Hermeneutic understanding

Understanding and explicating human behavior and texts.

• Describing meaningful relations in context.

• Interpreting individual cases (no laws).

• Motives and reasons (not causes).

• Actions (not movements).

• Hermeneutic circle of whole and parts.

Problem : no objectivity, not verifiable or falsifiable

B&LdeJ 6

Explaining Understanding

Natural sc.

• Time-spatial events

• Causes

• Nomothetical

• Object / objectivism

• Method-oriented

• Generalising over objective facts

Experimental, biological psychology

Social sc./humanities

• Actions

• Reasons (motives)

• Idiographical

• Subject / subjectivism

• Meaning-oriented

• Unique events

• Persons experience

Client-centered therapy, psychoanalysis

B&LdeJ 7

Reasons and causes in social science

• Explaining or understanding behavior?

• Action (rational, goal-directed, meaningful,motivated).

Or

• Movement (mechanical, causal, determined).

• Solution: multiple levels of explanation, understanding and causal explanation can coexist.

B&LdeJ 8

Functional explanations

What an item does , what goal it serves; not what it is (made of).

Teleology (goal-directedness).

The presence of a trait is explained by its function, e.g., mammals have a heart to pump blood.

Characteristic for biology: adaptive functions selected in evolution.

Evolutionary psychology : function of jealousy, cheater detection, etc. (see Ch. 9.2).

B&LdeJ 9

Functional explanations

The presence of a trait is explained by its function.

Adaptation (not physical causation, not interpretation of meaning).

How system works, its design and functioning (no laws, no causes, no predictions).

Problem: danger of cheap, circular, pseudoexplanation (adaptationism).

B&LdeJ 10

Mechanistic explanation

Extension of functional explanation.

A phenomenon is explained by the orchestrated functioning of the component parts of a mechanism.

E.g., heart (mechanism) pumping blood

(phenomenon) by muscles and valves

(components) together.

Interlevel: lower level of components explains higher level phenomenon.

B&LdeJ 11

Function

Etiological: the trait is selected in the past for a specific effect:

 evolutionary explanation.

Causal role: the contribution a trait makes to the capacity of the whole system:

 systemic, engineering explanation.

B&LdeJ 12

Functionalism

Is a materialistic notion of mind

Behaviorism: no mental terms and things; only observables.

Mind-brain Identity theory: mind is brain; mental terms have to be reduced to brain terms.

Functionalism: materialism without reductionism.

B&LdeJ 13

Functionalism

A mental process is a functional organisation of a machine (e.g., brain), an ‘abstract’ organisation, can be realised in different kinds of hardware.

‘ Token materialism’: every function is realised in something material.

No ‘ type materialism’: realisation in different kinds of material objects (computers, brains).

Therefore no reduction to neurophysiology.

B&LdeJ 14

Materialism in history

1913 – ca1950 ca 1950

1950 – 1985

1985 – present

Behaviorism (behavior)

Identity theory (mind=brain)

Functionalism: ‘1st cognitive

Revolution’ (cognition)

‘2nd cognitive revolution’

(cognition, brain & behavior)

B&LdeJ 15

Two forms of

mind

materialism

Type materialism of the Identity theory:

‘I’m afraid when typical brain cells are firing’

Token materialism of functionalism:

‘I’m afraid when my cognitive system is in a certain functional state’

B&LdeJ 16

Type and token

The tokens : student A student B

The type , the class : students

B&LdeJ 17

Problems of type materialism (IT) according to functionalists

• We have insufficient knowledge of brains.

• Autonomy of psychology, no reduction

(identity) of psychological to neural processes.

• IT is too ‘chauvinistic’: only human brains can show intelligence; but how about a chess computer?

B&LdeJ 18

Functionalism

Mental states are functional states of physical systems.

Functions have a causal role (cause other mental states and behavior).

Functions are materially though multiply realised.

Implementation is irrelevant for explanation.

Liberalism: computers, animals, aliens can show intelligence.

B&LdeJ 19

Criticism of biologically-oriented

Functionalists

This is machine functionalism: function is stripped of goal-directedness and adaptation.

Therefore: teleological functionalism; biological functions, not abstracted from implementation or environment.

B&LdeJ 20

Reduction and reductionism

Reduction: explanatory strategy

Explain complex phenomena by reducing to elements; chain of ‘why’ and ‘because’ going down from everyday macro-objects to elementary particles.

Reductionism: ideology

Reality is nothing but matter in motion (‘nothing buttery’), e.g., pain is firing of certain neurons; e.g., altruism is nothing but the blind instinct, programmed by a selfish gene.

B&LdeJ 21

Theory reduction

Theory reduction: deducing a higher level theory from more basic theories plus bridge laws (extension of D-N explanation): e.g., deduce thermodynamics (temperature and pressure) from statistical mechanics (molecules).

Bridge laws connect theories, identifying terms (things) across theories (e.g., temperature is average kinetic energy of gas molecules): e.g., associative learning deduced from synaptic potentiation; Long Term and Short Term Memory deduced from LTP (biochemistry); ‘neural alphabet’

(Kandel).

B&LdeJ 22

Classical reduction

Deducing higher level science from lower level; requires connectability (bridge laws) and deducibility sociology  psychology  neurofysiology  physics complex  simple.

• ‘Unified science’

(positivism): same kind of observations, same kind of explanations everywhere in science, ultimately ‘ideal physics’.

Basic theory incorporates higher level theory e.g., Mendelian genetics subsumed under biochemistry

(DNA).

B&LdeJ 23

Classical reduction

Deducing higher level science from lower level, connected by bridge laws; smooth incorporation of reduced (old) in reducing (new) theory.

Problem: Old theory usually false, concepts do not refer.

New theory corrects old, meaning of concepts changes.

Therefore, no bridge laws, no deduction.

Classical reduction fails as account of real scientific progress works.

Then:

• eliminativism : drop old theory (and its world view);

• or functionalism : non-reductive materialism, autonomy.

B&LdeJ 24

Non-reductive materialism

Multiple realisation: classical reduction impossible in neuro-psychology: no bridge laws (type identities) between mind and brain.

Supervenience: Mental processes determined by

(dependent on) material processes. No change in mental states without change in neural process (i.e., no disembodied mind).

Compatible with functionalism as theory about the mind:

• autonomy for psychology, no reduction;

• but also materialism, no dualism.

B&LdeJ 25

Supervenience: the mental and the neural mental mental no reduction determination neural1 neural2 neural3

B&LdeJ 26

Reduction vs elimination

Reduction : identification of higher level phenomenon with lower level.

Retains ontology: the reduced phenomenon really exists e.g., water is H

2

O; temperature is kinetic energy; e.g., pain is (identical with) firing of certain neurons.

Problem: old theory false, meaning changes: no bridge laws, no reduction.

Eliminativism: replacing higher level entities and theories by more fundamental ones.

Replaces ontology: higher level entities do not really exist e.g., talk of neural processes replaces ‘pain’,

‘consciousness’, ‘meaning’ etc.

B&LdeJ 27

New wave reductionism, eliminativism

• Responds to failure of classical reduction: higher level eliminated.

• Old reduced theory is to some degree false, obsolete, or incomplete.

• Old reduced theory to some degree corrected or even entirely replaced by lower level reducing theory.

• Functional, psychological theories only approximate, coarse descriptions.

• Cognitive phenomena can better be explained by neuroscience.

B&LdeJ 28

Reduction vs levels

• Reduction in D-N-model : unification, psychology is neuroscience.

• Eliminativism : psychology replaced by neuroscience:

• these are one-level stories.

• Alternative: multiple levels of explanation:

• explanatory pluralism , co-evolution of theories at different levels.

B&LdeJ 29

W

hen classical reduction fails

1. Autonomy (functionalism), or

2. Elimination (more or less correction of the reduced theory), or

3. Explanatory pluralism (McCauley) coexisting theories, mutually influencing each other top-down and bottom-up.

B&LdeJ 30

Explanatory pluralism

• Multiple levels of explanation coexist and coevolve.

• No autonomous levels (unlike functionalism), but mutual selection pressure.

• No reduction or elimination.

B&LdeJ 31

Download