Nursing Knowledge Chapter 8

Logical positivism and mid-century philosophy of science

Presented by Justin Fallin

October 25, 2014

Professor: Dr. Tomlinson

BEF 644

History and Terminology Empiricism

• Philosophical approach to learning about knowledge with a belief that everything comes from a person’s experience.

• Differs from Rationalism

• Rationalists: knowledge does not require experience, observation, or experiments.

• Empiricism: “our” knowledge of the world

• Rationalism: knowledge of things in the world

(Risjord, 2010)

Logical Positivism • Developed from empiricism.

• Formed from philosophers in the Vienna Circle: Schlick and Neurath , in Europe after the First World War (Godfrey-Smith, 2003)

• Peak of influence in the 1930s-1940s

• Positivists believed:

• All meaningful statements required verification

• If unverifiable, it is essentially useless

• As a result, it leaned toward scientific method

• Science is not observable- they wanted to prove unobservable could be meaningful

(Risjord, 2010)

Theory in Nursing

• Postulates: basic terms of a theory

• Propositions: parts of the definition of a theory arranged deductively.

• Axioms: basic propositions assumed true but not tested

• Theorems: propositions developed from axioms that can be deduced

1. Core of Theory: postulates or axioms

2. Postulates contain terms implicitly defined by postulates

3. Theorems develop from those postulates

• Euclid’s Geometry

• Axioms: first set of proofs but not proven

• Axioms proved all truths in geometry– thus, becoming theorems

• Axiom is true= theorem is true

• Is it acceptable to assume all axioms to be true?

• Positivists would say yes because of observable consequences

• Implicit Definitions

• Euclid’s definitions required prior knowledge of the terms

• All words cannot be defined because they would all reference each other

• Primitive terms are left without specific definitions to avoid this circularity

(Risjord, 2010)

Theory Structure Received View

• If knowledge comes from experience, scientific knowledge must be from observation

• To prevent such biases, positivists defined two terms:

• Observational vocabulary: objective terms such as “blue car,” “going 200 mph”

• Theoretical vocabulary: cannot be verified (observed) directly such as germs, air, wind

• Scientific theory has the following structure:

• Theoretical vocabulary

• Axioms expressed in theoretical vocabulary

• Bridge laws to relate theoretical and observational terms (needed– theory of only theoretical terms cannot be tested)

Theoretical/Experimental Law

• Scientific research goes in two directions:

• Empirical: inductively finds observable regularities

• Theoretical: speculative, uses postulates to form with theoretical terms

• Hierarchy of Theory

• Fundamental Laws: implicit definitions for fundamental concepts. (Newton’s law of motion)

• Middle-range Theories: experimental law or empirical generalizations. (apply Newton’s law to the tides)

• Ultimately, all laws can be reduced to physics but this seemed impossible as one domain cannot reduce to another.

(Risjord, 2010)

Explanation and TestingExplanation

• Empirical regularities that show a consequence of fundamental laws are “explained” phenomenon

• Per Hempel, explanation requires:

1. Event or empirical regularities to be explained (explanadum)

2. Number of general laws

3. Set of initial conditions (2 & 3 are grouped together= explanans)

• Known as the deductive-nomological conception of explanations

Testing Theory• Empiricism says all theories are

tested through observation

• Per received view, to test a theory:

• Proposition can be observed as true or false (hypothesis)

• Bridge laws are required to deduce the hypothesis

• If the theory proves false, theory is mistaken in some way

• According to Popper, theories are never true so scientists should be attempting to prove theories false through testing

(Risjord, 2010)

Conclusion• Received view became core to understanding scientific view.

• Using axioms, unobservables may be accepted to empiricists

• For positivists, scientific knowledge is the fundamental knowledge of the laws of nature

• Good theories are explanatory

• Science should produce theory and test it

• Disciplines considered basic sciences should have their own body of laws, consisting of theories and conceptual frameworks for that basic science

(Risjord, 2010)

References

• Godfrey-Smith, P. (2003). Theory and Reality. Chicago, IL: The University of Chicago Press.

• Risjord, M. (2010). Nursing Knowledge. Ames, IA: Wiley-Blackwell.