Changes

In the Aufbau, Carnap builds a hierarchical system where primary sensory information, called ‘elementary experience’, is the basis of empirical knowledge. From there, experience or observational statements are unified to statements of science, which describe the quantitative relation between the elements of experience. These rules of science are synthetic a posteriori, but are structured and organized to have formal properties resulting from constructional definitions and logical laws, which are analytic a priori .[[CiteRef::Cirera (31994)|pp. 1-42]] Building on Kant’s distinction of analytic/synthetic propositions, and a priori/a posteriori knowledge explained in Historical Context, Carnap modifies Kant’s analyticity criteria of containment by using a logic criteria, meaning that if a statement is purely logical it is analytic, while all other statements are synthetic. Carnap replaces Kant’s justification using a priori forms to justification in the form of modern logical relations between the observational synthetic statements and the infallible a priori logical laws that structure them .[[CiteRef::Rey (142017). ]]

In [[Carnap (1937c)|“The Logical Syntax of Language” ]] (1934, English Tran. 1937)(link), Carnap formulates the distinction between analytic and synthetic statements in a boarder context of linguistic frameworks. For Carnap, a linguistic framework of science is comprised of two kinds of rules :[[CiteRef::Friedman (52002):]]

By defining the rules of the framework, Carnap is able to give a syntactic formulation of logical consequence, where L-rules are logically determined and are independent of experience and defined as analytic a priori. Statements that are not logically determined are defined as synthetic statements .[[CiteRef::Murzi (62017). ]] This formulation builds on the analytic/synthetic distinction made in the Aufbau, using a different taxonomy.

In Logical Syntax, Carnap posit posits the idea of linguistic frameworks to allow for changes in the appraisal or value of a scientific theory. He employs this idea of frameworks to explain changes in mathematical and logic laws in the foundation of science, as this has occurred with the replacement of Newtonian to Einsteinian worldview. Carnap argues for a Principle of Tolerance, which declares that there are no absolute rules of logic, meaning changes in L- rules will yield different frameworks with different appraisal methodologies and their choice is conventional. For Carnap, both L- and P- rules are subject to change within a framework to accommodate new scientific evidence .[[CiteRef::Friedman (52002). ]]

Later in 1952 [[Carnap (1952b)|“Meaning Postulates” (link)]], Carnap clarifies his criteria of analyticity in the form of meaning postulates, logically true by meaning of words, or put more simply by language definition .[[CiteRef::Rey (142017). ]]

===Demarcation Between Science and Pseudoscience – Scientific Significance ===

In the Aufbau, and later and more directly in “testability [[Carnap (1936)|“Testability and Meaning”(link) ]] Carnap develops criteria for distinguishing scientific statements from non-scientific or pseudoscientific ones. Scientific statements must comply with the Verification Principle, that is, they must be verifiable through experience .[[CiteRef::Cirera (71994)|pp.149-168]]

Carnap’s choice in the Verification Principle, is also influenced by its consequences to metaphysics. It creates a barrier that differentiates scientific physical statements from speculative metaphysics statements. Verification is regarded as meaning criteria, where verifiable scientific propositions are considered meaningful, while metaphysical propositions are meaningless since they are not funded in experience. This view is also called Carnap’s Physicalism and is proposed for the value of directing science away from metaphysics, which according to Carnap, impede science from conducting in a fruitful way .[[CiteRef::Cirera (71994)|pp.149-168]]

Throughout his career Carnap has attempted in different formulations to employ the tools of probability and induction to the question of theory choice. Carnap’s motivation is to use these tools to produce a quantitative assessment to a degree of confirmation of a scientific theory .[[CiteRef::Zabell (82008). ]] Carnap’s inductive logic attempts to formulate a logical relationship between a scientific statement or theory and a single observational evidence supporting that statement. If successful, this will solve Hume’s problem of induction by shifting from absolute certainty to different degrees of confirmations that will allow to rationally choose between two competing scientific theories .[[CiteRef::Murzi (62017). ]] This has been the focus of Carnap’s work from 1940s until he died (4), and although he tried numerous mathematical tools and logical formulations, he did not succeed in constructing a satisfactory theory of inductive logic.[[CiteRef::Friedman (2002)]]