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Theoretical Issues in Psychology

Philosophy of Scienceand

Philosophy of Mindfor

Psychologists

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Aims of the book

Review of basic ideas and problems in philosophy of science and philosophy of mind, relevant for psychologists.

Psychology as science of mind:• what is science? Chapters 1–5.• what is mind? Chapters 6–10.

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Chapter 1Science: why and how?

• Why science?• Knowledge• Arguments• Laws, theories, models and causes

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Why and how?

Demarcating science:• science as arbiter of objectivity and truth;• demarcating science from pseudoscience;• science as safeguard against propaganda and superstition.

Objectivity vs subjectivity or human construction:• realism, foundationalism, objectivism (positivism Ch. 3).• relativism (social constructionism, sociology of science

Ch. 4 and 5).

But what defines science?

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What defines science?

• Reduction: underlying causal structure explains macro-phenomena; this research produces …• Unification; and promotes …• Systematicity.

• Critical attitude: against authority and dogma; inspires freedom of thought, advances enlightenment and …• Open-mindedness.

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Theories of truth

Traditional theories of truth:

Correspondence theory of truth

Coherence theory of truth

‘Recent’ theories of truth:

Consensus theory of truth

Pragmatic theory of truth

Correspondence theory: a statement or belief is ‘true’ if it corresponds with a situation,

an event or an object in reality, or in the world(realism – objectivism)

‘There is a cat on the mat!’

=>

correspondence

Coherence theory: a statement or belief is called ‘true’ if it is coherent with other beliefs

(knowledge) that one has (idealism / relativism)

‘There is a cat!’‘A cat is a mammal of

the genus Felix;a pet animal,

with a soft skin,that likes to be carressed

etc., etc.’

coherent with

• Consensus theory: ‘truth’ is a social

or cultural consent or approval

(relativism / social-constructionism)

• Pragmatic theory: a belief or theory is ‘true’ or reliable if it has success in practice; if it can be established by experience (experiments)

‘Recent’ theories of truth

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Realism:Realism:• world exists knower-independent;world exists knower-independent;• world is primary;world is primary;• knowledge pictures the objective world (representing);knowledge pictures the objective world (representing);• truth is correspondence between knowledge and world.truth is correspondence between knowledge and world.

Relativism (Relativism (an extreme version:an extreme version: Idealism): Idealism):• world is (partly) constructed by the knower (subject);world is (partly) constructed by the knower (subject);• subject is primary;subject is primary;• knowing is constructing;knowing is constructing;• truth is coherence with the rest of knowledge, or consensus.truth is coherence with the rest of knowledge, or consensus.

Pragmatism:Pragmatism:

• knowledge is functional and active, coping with the world;knowledge is functional and active, coping with the world;• truth is practically, experientially successful.truth is practically, experientially successful.

Views on world & knowledgeViews on world & knowledge

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A problem for realism: ‘God’s eye view’

How to compare the world with a theory, since one can never get outside one’s theory (opinion)? Irony: only in ‘God’s eye’ can correspondence be assessed.

World Theory

OK!

correspondence

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Pragmatic realism

Hillary Putnam (‘pragmatic realism’): ‘the mind and the world jointly make up the mind and the

world’ (cf. Kant)

World features

Categories,interests

‘World’

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Everyday knowledge and science

Conclusion: different perspectives, both real

Eddington’s ‘Two Tables’:

• molecules, empty, weightless, colorless;• visible, solid, colored everyday object.

What is the real table? Everyday world as illusion?

Everyday knowledge and scientific knowledge:• ‘manifest’ vs ‘scientific image’ (Sellars);i.e. visible vs underlying, explanatory image

(bv. water – H2O; depression – dopamine)

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Characteristics of science

1. Systematicity: a coherent system of theories, statements, formulae etc.

2. Well-defined methods: methods specify what counts as legitimate problems, facts, solutions, etc.

3. Reduction: phenomena (or theories) are explained by underlying lower-level mechanisms (or laws).

4. Objectivity: in the sense of being controllable, reliable and inter-subjectively observable.

5. Clarity: scientific statements are phrased unambiguously, in principle addressed to the public domain.

6. Revisability: scientific knowledge is open, revisable at all times and never definitive.

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Induction, deduction, abduction

Induction: from individual observations to general statements.No logical certainty, but new knowledge.

Example: Lots of swans were observed; all were white.Maybe all swans are white.

Deduction: from general statements to individual.Logical certainty: conclusion contained in premises, but no new knowledge.

Example: All humans are mortal.Socrates is human.Therefore, Socrates is mortal.

Abduction: inference to the best explanation.No logical certainty, new hypothetical knowledge about causes

Example: All CJD patients ate beef. Beef may be the cause of CJD.

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The problem of induction

• Every generalisation can be disconfirmed by an unexpected observation (‘black swan’).

• Confirmation cannot, unlike deduction, be formalised; no logical certainty.

• Inducing requires classification; one has to start with concepts and criteria (e.g. for similarity).

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Facts and theories

• Facts: no such thing as pure observation; theory influences observation – ‘theory-ladenness’

• Theory (coherent set of statements) indispensable:• standard terms for description;• coherent, unifying;• ‘unobservable’ scientific concepts (e.g., energy,

IQ) connected to observations by theory.• Strict distinction between fact and theory

impossible; hierarchy from factual to theoretical.

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‘Justification’ vs ‘discovery’

Context of justification: normative, focus on method; prescribing criteria for holding a theory true, acceptable or justified, logically or empirically ( positivism).

Context of discovery: description of the historical, social and psychological circumstances and influences that were relevant to the invention or discovery of scientific theories: who, where and when? ( more or less relativistic views of science).