This volume is a collection of Rudolf Carnap’s writings on pseudo-problems and the critique of metaphysics. Its center is the short monograph Scheinprobleme in der Philosophie, whose subtitle identifies its two main case studies: the “foreign-psychical” (the problem of other minds) and the realism dispute. The other texts gathered with it extend the same program: they use logical analysis of language to distinguish genuine scientific or logical questions from questions that only appear to be substantive.
The central monograph argues that many traditional philosophical problems are pseudo-problems. Carnap does not deny that there are meaningful questions about other people’s experiences or about the empirical world. He denies that the traditional metaphysical versions of these questions have cognitive content. A genuine question must be answerable in principle by empirical test or by logical analysis; a pseudo-question lacks any possible experiential or logical decision. The problem of other minds, when posed as a question about whether there is some hidden “mind” behind observable behavior, is treated as such a pseudo-problem. Statements about other people’s pain or perceptions are meaningful when they are tied to intersubjectively observable behavior and circumstances. What is rejected is the metaphysical demand to prove or deny the existence of other minds as unobservable entities separate from all possible evidence.
The same strategy is applied to the realism–idealism dispute. Carnap argues that the metaphysical theses “the external world is real” and “the external world is merely ideal” are not empirical hypotheses. No possible experience could decide between them, and therefore neither has the status of a scientific statement. The empirical realist, who takes material objects as the objects of ordinary and scientific investigation, is not making a metaphysical claim; the metaphysical realist and the metaphysical idealist are both making pseudo-statements. The dispute dissolves once one sees that the reality of the external world is not a further fact to be established alongside empirical facts, but a framework within which empirical inquiry operates.
The accompanying writings develop this critique of metaphysics in several directions. One central theme is the logical analysis of metaphysical language. Carnap argues that metaphysical sentences are pseudo-sentences: either they contain words that have no clear empirical application, or they combine meaningful words in ways that violate logical syntax while superficially resembling genuine assertions. Such sentences may express a practical attitude, a feeling about life, or a poetic vision, but they do not convey theoretical knowledge. Logical analysis therefore has a therapeutic or clarifying task: it shows why metaphysical questions arise and why they cannot be answered as factual questions.
A second theme is the unity and universal character of scientific language. Carnap defends the idea that the language of physics can serve as a universal language of science, into which the statements of the special sciences can be translated. This is connected with his critique of a metaphysical conception of psychology: psychological statements are not about a private, inaccessible mental substance. They are meaningful insofar as they are related to behavior and to physical states of organisms. The mentalistic metaphysics of mind is thus replaced by the logical analysis of psychological language.
A third theme concerns the nature of ontology. In the later essay Empirismus, Semantik und Ontologie, Carnap distinguishes questions that are internal to a linguistic framework from external questions about the “reality” of the framework itself. Internal existence questions—for example, whether there are numbers or physical objects within a given conceptual system—can be answered by empirical or logical procedures. External questions about whether the framework as a whole corresponds to reality are not cognitive questions to be answered by metaphysical insight; they are practical questions about which framework to adopt. Metaphysical ontology, which treats framework existence as a factual matter, is therefore another source of pseudo-problems.
The collection also includes programmatic texts on the transition from traditional epistemology to the logic of science. Traditional epistemology is criticized for seeking a special first-person foundation for knowledge; it is replaced by the logical analysis of scientific statements, their confirmation relations, and their linguistic form. The essays on protocol sentences and physical language belong to this same enterprise: they examine how scientific statements are tested and how the language of observation is related to theoretical language.
Overall, the book presents a unified campaign against metaphysical pseudo-problems. Its recurring claim is that many philosophical disputes—about other minds, realism, the mental, and ontological existence—arise from treating grammatical or expressive sentences as if they were factual claims. Once the logical form and empirical conditions of meaningful statements are clarified, these disputes either become genuine scientific questions or disappear. The volume does not offer a single continuous narrative; its unity lies in the repeated application of logical analysis to the task of separating sense from pseudo-sense in philosophy.
The collection’s method is consistently comparative: it asks what difference a proposed metaphysical thesis would make to possible experience. If two positions—say, empirical realism and transcendental idealism—agree on every observable prediction and differ only in how they describe the same empirical situation, then their disagreement is not factual. It is a difference in the choice of language, and the metaphysical formulation of that difference turns a practical decision into a pseudo-question. This is why the essays repeatedly replace questions about “reality” with questions about the logical role of expressions within a framework.
A related analysis concerns the “given.” The collection argues that the search for a pure, preconceptual datum is itself a pseudo-problem. Reports of immediate experience are already formulated in a language and are therefore intersubjectively testable; they are not private foundations. The discussion of observation statements is not an attempt to find an indubitable basis for knowledge but an attempt to clarify how such statements function within the system of science. The “given” is not a metaphysical entity but a role within a linguistic framework.
The critique of metaphysics also includes a logical diagnosis of terms that appear to name objects but function differently. Words like “nothing” or “being” can be used meaningfully in ordinary contexts, but metaphysical sentences treat them as names of special entities or processes. The analysis shows that such sentences violate logical syntax: they combine expressions in ways that do not yield a truth-evaluable claim. This is not a matter of empirical ignorance but of logical form.
The collection’s positive program is not a new metaphysics but a logic of science. Philosophy becomes the analysis of the language of science: the clarification of confirmation relations, the translation of statements between frameworks, and the distinction between logical and empirical questions. The unity of science is proposed as a common linguistic framework, not as a claim that everything is ultimately physical in a metaphysical sense. The physical language is recommended because it makes intersubjective testability explicit, not because it reveals the ultimate nature of reality. In the ontology essay, the adoption of a framework is evaluated by pragmatic criteria—fruitfulness, simplicity, and service to inquiry—rather than by a metaphysical correspondence to reality.
