Carnap: Confirmation and Verification

In Der logische Aufbau der Welt, first published in 1928, Carnap aims to rationally reconstruct all objects of cognition by logico-definitional means. As a result, he intends to obtain a fully objective framework in which scientific discourse can take place. This is made possible by the novel method of ‘purely structural definite description’ of all scientifically relevant objects, which is first introduced in the Aufbau. Key to the attainment of this goal is the notion of ‘foundedness’, which Carnap presents as (...) a new basic notion of logic, in order to establish a link between the purely conventional world of logical and mathematical knowledge and the empirical world of knowledge of scientific objects. This idea experienced major criticism by Friedman (1999a,b) since he considers it to lead to the demolition of the boundary between those two worlds. In this essay, we want to defend foundedness against Friedman’s critique by arguing that its introduction is necessary within Carnap’s logicist world of thought to deal with a more fundamental problem: the demarcation of the empirical parts of the Aufbau. In the last section, we will give an outlook on the actual cause for the failure of the Aufbau, the lack of a principle to determine the truth of the instances of the basic relation in the Aufbau, and we will show how this can contribute to the explanation of Carnap’s future philosophical development and retrospective self-evaluation. This essay serves as a dense informal sketch for a later extensive formal treatment of this reading of foundedness and focuses on its implications for the interpretation of Carnap’s post-Aufbau development. (shrink)

Many who take a dismissive attitude towards metaphysics trace their view back to Carnap’s ‘Empiricism, Semantics and Ontology’. But the reason Carnap takes a dismissive attitude to metaphysics is a matter of controversy. I will argue that no reason is given in ‘Empiricism, Semantics and Ontology’, and this is because his reason for rejecting metaphysical debates was given in ‘Pseudo-Problems in Philosophy’. The argument there assumes verificationism, but I will argue that his argument survives the rejection of verificationism. The root (...) of his argument is the claim that metaphysical statements cannot be justified; the point is epistemic, not semantic. I will argue that this remains a powerful challenge to metaphysics that has yet to be adequately answered. (shrink)

In “Two Dogmas”, Quine indicates that Carnap’s Aufbau fails “in principle” to reduce our knowledge of the external world to sense data. This is because in projecting the sensory material to reconstruct the physical world, Carnap gives up the use of operating rules and switches to a procedure informed by general principles. This procedure falls short of providing an eliminative translation for the connective “is at”, which is necessary for the reduction. In dissecting Quine’s objection, I argue that Quine has (...) at best proven the claim that the use of general principles essentially fails the task of radical reductionism. However, in order to establish the conclusion that the Aufbau fails in principle, Quine needs to further vindicate two other claims. They are: first, a switch from operating rules to general principles is necessary; second, the set of general principles Carnap adopts is the best alternative. By disambiguating the notion of “explicit definition” and examining the concept of definability in the Aufbau, I explore the possibility of justifying these two claims that Quine overlooks in his objection. The result suggests that Quine’s objection stands in tension with his radical reductionist reading of the Aufbau. (shrink)

A brief introduction to the life and key work of Rudolf Carnap with special attention to his work on inductive logic.

In “Empiricism, Semantics, and Ontology” Carnap drew his famous distinction between ‘internal’ and ‘external’ questions of existence, pronouncing the former meaningful and the latter meaningless. In The Significance of Philosophical Scepticism, Barry Stroud understands Carnap to be applying the verification criterion of meaningfulness in order to refute Cartesian skepticism. I suggest that Stroud misrepresents both Carnap’s aim and method. Carnap was responding to critics who suggested that his willingness to quantify over abstract entities in his work in semantics violated his (...) commitment to empiricism. He rejected that criticism as presupposing a super-scientific standpoint from which constraints on the admissible domain of entities of science could be delivered. Carnap wanted to insulate science from the imposition of frrst-philosophical metaphysical prejudice, not to defuse scepticism by appeal to verificationism. (shrink)

The critical focus of this paper is on a claim made explicitly by Gilbert Harman and accepted implicitly by numerous others, the claim that naturalism supports concurrent defense of scientific objectivism and moral relativism. I challenge the assumptions of Harman's ‘argument from naturalism' used to support this combination of positions, utilizing. Hilary Putnam’s ‘companions in guilt’ argument in order to counter it. The paper concludes that while domain-specific anti-realism is often warranted, Harman’s own views about the objectivity of facts and (...) the subjectivity of values are better seen as stemming from scientistic ideals of knowledge than from dictates of naturalism. Scientists qua scientists make value judgments, and setting aside scientistic assumptions and unrealizable conceptions of scientific objectivity should lead us to more symmetrical metaphilosophical conception of epistemic and ethical normativity than that which underlies Harman's account. (shrink)

Inductive methods can be used to estimate the accuracies of inductive methods. Call a method immodest if it estimates that it is at least as accurate as any of its rivals. It would be unreasonable to adopt any but an immodest method. Under certain assumptions, exactly one of Carnap's lambda-methods is immodest. This may seem to solve the problem of choosing among the lambda-methods; but sometimes the immodest lambda-method is λ =0, which it would not be reasonable to adopt. We (...) should therefore reconsider the assumptions that led to this conclusion: for instance, the measure of accuracy. (shrink)

In recent years, a revisionist process focused on logical positivism can be observed. One aspect of this revisionism -defended by authors like Michael Friedman, John Earman and George Reisch - is the thesis that Carnap’s later thought is compatible with that of Kuhn and even that Carnap anticipates some relevant points of Kuhn’s theory of science. In this paper I discuss one of Carnap’s texts most frequently cited by revisionists in favor of their thesis -"Truth and Confirmation" - trying to (...) put it in the context of Carnap’s work. My intention is to analyze revisionist interpretation on the basis of other texts by Carnap and show that revisionists, while assembling their jigsaw puzzle concerning Carnap’s work, have inadvertently forgotten to consider some pieces of importance in the formation of a theoretically and historically cogent picture. (shrink)

The attempt to explicate the intuitive notions of confirmation and inductive support through use of the formal calculus of probability received its canonical formulation in Carnap's The Logical Foundations of Probability. It is a central part of modern Bayesianism as developed recently, for instance, by Paul Horwich and John Earman. Carnap places much emphasis on the identification of confirmation with the notion of probabilistic favorable relevance. Notoriously, the notion of confirmation as probabilistic favorable relevance violates the intuitive transmittability condition that (...) if e confirms h and h' is part of the content of h then e confirms h'. This suggests that, pace Carnap, it cannot capture our intuitive notions of confirmation and inductive support. Without transmittability confirmation losses much of its intrinsic interest. If e, say a report of past observations, can confirm h, say a law-like generalization, without that confirmation being transmitted to those parts of h dealing with the as yet unobserved, then it is not clear why we should be interested in whether h is confirmed or not. The following paper rehearses these difficulties and then proposes a new probabilistic account of confirmation that does not violate the transmittability condition. (shrink)