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 • • • Logical Positivism Rationalists: knowledge does not require experience, observation, or experiments. Empiricism: “our” knowledge of the world Rationalism: knowledge of things in the world (Risjord, 2010) • • 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 • Euclid’s Geometry 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. 2. 3. • Postulates contain terms implicitly defined by postulates Theorems develop from those postulates • 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? • Core of Theory: postulates or axioms Axioms: first set of proofs but not proven 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 • • Observational vocabulary: objective terms such as “blue car,” “going 200 mph” • • • Theoretical vocabulary Axioms expressed in theoretical vocabulary Bridge laws to relate theoretical and observational terms (needed– theory of only theoretical terms cannot be tested) • Empirical: inductively finds observable regularities Theoretical: speculative, uses postulates to form with theoretical terms Hierarchy of Theory • Theoretical vocabulary: cannot be verified (observed) directly such as germs, air, wind Scientific theory has the following structure: • • • Scientific research goes in two directions: • To prevent such biases, positivists defined two terms: • • Theoretical/Experimental Law 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 Testing Explanation • • Empirical regularities that show a consequence of fundamental laws are “explained” phenomenon • • Per Hempel, explanation requires: 1. 2. 3. • Testing Theory Empiricism says all theories are tested through observation Per received view, to test a theory: • Event or empirical regularities to be explained (explanadum) • Number of general laws • Set of initial conditions (2 & 3 are grouped together= explanans) Known as the deductive-nomological conception of explanations • 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.