Editing Logical positivism (section)

===Observation-theory distinction===

{{See also|Ramsey sentence}}

[[Rudolf Carnap|Carnap]] devoted much of his career to the cornerstone [[doctrine]] of ''rational reconstruction'', whereby scientific theories can be formalised into [[predicate logic]] and the components of a theory categorised into ''[[Ramsey sentence|observation terms]]'' and ''[[Ramsey sentence|theoretical terms]]''.<ref name="sep-recon">{{cite encyclopedia |first1=Hannes |last1=Leitgeb |first2=André |last2=Carus |year=2020 |title=Supplement to "Rudolf Carnap": E. The Reconstruction of Scientific Theories |encyclopedia=The Stanford Encyclopedia of Philosophy |url=https://plato.stanford.edu/entries/carnap/reconstruct-sci-theories.html |access-date=2025-02-04 }}</ref> Observation terms are specified by direct observation and thus assumed to have fixed empirical definitions, whereas theoretical terms refer to the [[unobservable]]s of a theory, including [[abstract and concrete|abstract]] conceptions such as [[formula|mathematical formulas]]. The two categories of [[primitive notion|primitive terms]] would be interconnected in meaning via a [[deductive reasoning|deductive]] interpretative framework, referred to as ''correspondence rules''.<ref name=carnap-win>{{cite journal |first=John A. |last=Winnie |title=The Implicit Definition of Theoretical Terms |journal=J. Phil. Sci. |volume=18 |year=1967 |pages=223-229 }}</ref>

Early in his research, Carnap postulated that correspondence rules could be used to define theoretical terms from observation terms, contending that scientific knowledge could be unified by [[reductionism|reducing]] theoretical laws to "protocol sentences" grounded in observable facts. He would soon abandon this model of reconstruction, suggesting instead that theoretical terms could be defined implicitly by the [[axioms]] of a theory. Furthermore, that observation terms could, in some cases, garner meaning from theoretical terms via correspondence rules.<ref name="carnap-lt">{{cite book |first=Sebastian |last=Lutz |editor1=S. Lutz |editor2=A.T. Tuboly |chapter=Two Constants in Carnap’s View on Scientific Theories |year=2021 |doi=10.4324/9780429429835 |title=Logical Empiricism and the Physical Sciences |publisher=Routledge |pages=354-378}}</ref> Here, definition is said to be 'implicit' in that the axioms serve to exclude those interpretations that falsify the theory. Thus, axioms define theoretical terms indirectly by restricting the set of possible interpretations to those that are true interpretations.<ref name=carnap-win/>

By reconstructing the [[semantics]] of scientific language, Carnap's thesis builds upon earlier research in the reconstruction of [[syntax]], referring to [[Bertrand Russell]]'s [[logical atomism]]—the view that statements in [[natural language]] can be converted to standardised subunits of meaning assembled via a [[logical syntax]].<ref>{{cite book |last=Russell |first=Bertrand |chapter=The Philosophy of Logical Atomism [1918] |date=1988 |title=The Collected Papers of Bertrand Russell, Volume 8 |pages=157–244 |doi=10.4324/9781003557036-20 |location=London |publisher=Routledge |isbn=978-1-003-55703-6 |editor=John G Slater}}</ref> Rational reconstruction is sometimes referred to as the ''[[received view]]'' or ''syntactic view of theories'' in the context of subsequent work by [[Carl Hempel]], [[Ernest Nagel]] and [[Herbert Feigl]].<ref name=sep-recon/>