|Carnap's 'Elimination of Metaphysics Through Logical Analysis of Language'. A Retrospective Consideration of the Relationship between Continental and Analytic Philosophy
Gottfried Gabriel, Department of Philosophy, Friedrich Schiller University Jena, Germany.
Rudolf Carnap is a classic proponent of the ideal language school within analytic philosophy. He has divided opinion more sharply than other representatives of this tradition and thus contributed decisively to the ongoing separation of analytic and continental philosophy. The essay 'The Elimination of Metaphysics Through Logical Analysis of Languages' (Carnap 1931, 1959), in particular, contributed to the polarization because it made Martin Heidegger, the classic author of continental philosophy, the target of exercises in a logically inspired criticism of metaphysics.
The following essay reconsiders the relationship between analytic and continental philosophy, using the Carnap-Heidegger controversy as an example. We should bear in mind, however, that the roles of analytic and continental philosophy have in the meantime been strangely reversed. Whereas the continental tradition struggles above all with the deconstruction of supposed remnants of old metaphysics, a new metaphysics is celebrating its reemergence in logically ingenious theories of analytic philosophy. The order of the day is not an elimination of metaphysics, but its new foundation through the logical analysis of language. We would suppose that this development would have the disapproval of both Carnap and Heidegger. For example, Carnap would surely have accused the metaphysics of possible worlds (and his philosophical grandchild David Lewis) of confusing internal and external existence, whereas Heidegger would have critized such metaphysics as a kind of forgetfulness of Being of a presence-at-hand ontology (Vorhandenheitsontologie).
There are more profound reasons for assuming such agreement between Carnap and Heidegger. For it is not so much the attitude towards metaphysics itself, but their views as to what remains for philosophy to do following the end of metaphysics that constitutes the opposition between Carnap and Heidegger.1 This opposition shows in different forms of linguistic presentation, and indeed, it is primarily through linguistic differences that analytic and continental philosophers can be recognized today. Before pursuing this idea, we discuss the philosophical-historical setting of Carnap's and Heidegger's thinking to display their common ground.
To begin, we should remember that the distinction between analytic and continental philosophy is problematic in two ways. Firstly, the two designations are askew, because 'analytic' is a methodological determination, whereas 'continental' is geographical. Secondly, the implicit geographical division, according to which all analytic authors are assumed to be Anglo-Saxon, doesn't work. The ranks of analytic philosophy include, along with Carnap, G. Frege, B. Russell, G. E. Moore, L. Wittgenstein, G. Ryle and J. L. Austin. Frege, Wittgenstein and Carnap not only come from the Continent, but also received their essential intellectual formation there (Frege and Carnap in Jena, Wittgenstein in Vienna).
With regard to Carnap and Heidegger their philosophical beginnings at least are congruous, albeit with different emphasis. Both received their initial education in the context of Neo-Kantianism: Carnap under B. Bauch in Jena, Heidegger under H. Rickert in Freiburg. (During his time in Freiburg, Carnap also heard Rickert.) Carnap was influenced decisively by Frege, and Heidegger in a corresponding manner by Husserl. Both concurred with the anti-psychologistic logism of their respective teachers in the form of a theory of validity (which goes back to H. Lotze). Both, however, also acknowledged the other tradition: the early Heidegger (1912, 20) refers to Frege, and the young Carnap to Husserl.2 Whereas for Carnap the distinction between validity and genesis of statements remained decisive throughout his life, Heidegger, under the influence of life-philosophy (W. Dilthey, F. Nietzsche), distanced himself from linking the concept of truth to statements, that is from the propositional concept of truth, essential for the logical tradition since Aristotle.
This difference concerning the nature of truth drives Carnap and Heidegger in differing directions. But this difference did not arise through Carnap's having paid no attention to life-philosophy. Instead, here too the initial situation for Carnap and Heidegger is identical. Both experienced the contest between Neo-Kantianism and life-philosophy at the beginning of the twentieth century. Central to this conflict was the question regarding the relationship between logic and life and — proceeding from this question — the determination of the task of philosophy. The result was that the two Neo-Kantians treated the challenge of life-philosophy in different ways. For Heidegger the course was set by Husserl, and for Carnap by Wittgenstein. Their paths parted for good with Heidegger's inaugural lecture in Freiburg What is Metaphysics? (Heidegger 1929). Carnap had previously taken part in the famous dispute between E. Cassirer and Heidegger in Davos. Although the independence of Heidegger's thinking had also impressed Carnap, he remained philosophically bound to the rationalistically oriented Neo-Kantianism as represented by Cassirer. By taking his examples of meaningless metaphysical statements from Heidegger's inaugural lecture in particular, he sent a signal, for, as he emphasized, he might "just as well have selected passages from any other of the numerous metaphysicians of the present or the past" (Carnap 1959, 69, footnote 2).
The list of metaphysicians adduced by Carnap as examples (Fichte, Schelling, Hegel, Bergson, Heidegger) displays a large degree of agreement with the usual enumeration of continental authors with one important exception. Nietzsche, who in today's controversy is viewed (by both sides) as a model author in the continental tradition, is spared in Carnap's criticism. This fact has not been appreciated sufficiently until now, not least because with his move to the USA, Carnap had cut or at least suppressed his own continental roots in orienting himself to the new philosophical circumstances, especially to the pragmatism found there.3 In his intellectual biography only weak traces of the continental tradition are recognizable, and even these have been ignored.
For several years a historical reconsideration of the origins of analytic philosophy that seeks to revise its 'forgetfulness of the Continent' has been in progress. After Frege had found his fixed place in Neo-Kantianism (cf. Gabriel 2002), Carnap's relationship with this tradition, which dominated German philosophy at the turn of the century, has been largely investigated (cf. in particular Richardson 1998). A part of Carnap's continental roots have thus been revealed.
M. Friedman has presented the first thorough historical study of the relationship between Carnap and Heidegger, in which he attempts to show how, by dealing with the same basic ideas of Neo-Kantianism, two traditions of philosophy were able to develop which have led to the current opposition of analytic and continental philosophy (Friedman 1996). One factor, however, which Friedman does not take into account is the role of life-philosophy.4 It is only by considering this that the picture is completed and the actual differences are brought into the open. The final section of Carnap's (1931) essay, entitled "Metaphysics as expression of an attitude towards life (Lebensgefühl)", provides important clues here. The expression "Lebensgefühl" is a central term for W. Dilthey. Presumably Carnap adopted the term not directly from Dilthey, but from his student Herman Nohl, whom Carnap had heard in Jena.5 It is revealing that, apart from Bauch and Frege, Nohl is the only one of his teachers in Jena that Carnap mentions by name in his Intellectual Autobiography. And this mention is not limited to academic reasons. Carnap writes:
"I remember with special pleasure and gratitude the seminars of Hermann [correctly: Herman, G. G.] Nohl (at that time a young instructor in Jena), in philosophy, education, and psychology, even when the topic, for example, Hegel's Rechtsphilosophie, was often somewhat remote from my main interests. My friends and I were particularly attracted by Nohl because he took a personal interest in the lives and thoughts of his students, in contrast to most of the professors in Germany at that time, and because in his seminars and in private talks he tried to give us a deeper understanding of philosophers on the basis of their attitude toward life ("Lebensgefühl") and their cultural background." (Carnap 1963, 4)
The personal element addressed here has its place in Carnap's life itself. The "friends" (such as the later pedagogue Wilhelm Flitner) were committed members of the German youth movement with whom Carnap bounded through the Jena woods. The "deeper understanding of philosophers" mentioned here amounts to discerning their respective Lebensgefühl as the driving force of their differing metaphysics. The basis of such an assessment, which Carnap adopted from Nohl, is Dilthey's Weltanschauung doctrine. Before turning to this as the actual 'point' of Carnap's 'Elimination of metaphysics', I would first like to expand on the methodological framework as set out in Carnap's essay (1931).
The basic features of the criticism of metaphysics developed by Carnap, namely the linking of formal logic with the principle of verifiability are not new: they had already been worked out in Wittgenstein's Tractatus, to which Carnap explicitly refers. The familiar problems with the formulation of the empiricist criterion of meaning are not to be elaborated here. Difficulties already result from the fact that the meaning of a sentence is supposed to be determined by its truth conditions (cf. Carnap 1959, 62). Meaning is hence linked to the form of statements, and is reduced to propositional meaning. Accordingly, normative statements are considered meaningless by Carnap: "It is altogether impossible to make a statement that expresses a value judgment." (ibid., 77) Now the criterion of meaning is not to be understood as a merely descriptive criterion of distinction, but as a normative criterion of exclusion and hence falls prey to its own verdict of meaninglessness.6
In comparing Carnap and Wittgenstein, an important terminological difference is to be noted. For Wittgenstein the only statements (propositions) that have sense are those that describe logically possible facts (in the sense of existent or non-existent states of affairs). Already the statements of logic lack sense. This determination is not to be understood pejoratively, but merely as characterizing their status as logically true, i.e. as tautologies, that say nothing about the world. Carnap, however, understands these statements as being meaningful because they are "true solely by virtue of their form" and follows Kant in defining them as analytic statements (Carnap 1959, 76). Accordingly they are valid a priori. Alongside analytic statements Carnap recognizes empirical statements corresponding to Kant's synthetic a posteriori statements. As distinct from his Jena dissertation Der Raum (1921) Carnap now denies the possibility of a priori synthetic statements.
Carnap speaks of meaningless statements (sinnlose Sätze) when words without meaning occur in them, or when they are not correctly logically syntactically formed. The meaningless statements in Carnap's terminology thus correspond to the nonsensical (unsinnigen) propositions in Wittgenstein's terminology.7 The thesis that words without meaning occur in metaphysical texts is old. It is stated emphatically, for example, by D. Hume. New, however, is the view that there exist statements in which the logical syntax is violated, though they accord with historical-grammatical syntax (cf. Carnap 1959, 69). This insight goes back to Frege and was first developed into the basis of a criticism in principle of metaphysics by Wittgenstein in the Tractatus. The basic features of this criticism are adopted by Carnap. The consequences he sees are admittedly quite different from those of Wittgenstein.
Whereas Wittgenstein's farewell to metaphysics was not without sadness, Carnap cheerfully issues the command for philosophy of science to 'clean up' and allows philosophy to be absorbed by the logic of science. This 'way out' is ruled out for Wittgenstein because for him a metalogic that attempted to 'say' once again what can only 'show' itself is impossible. The categorial discourse that sets out the logic of our language is compelled to overstep the limits of this logic. This discourse itself breaks the rules of syntactic well-formedness that it seeks to explicate. Hence not only are the statements of traditional metaphysics nonsensical, but so too are those statements in which this criticism is formulated, in particular therefore the statements of the Tractatus itself.
This view has consequences for the form of presentation of Wittgenstein's texts, a form which must be called literary rather than logical. Wittgenstein's Tractatus presents logic as literature. It is no wonder that through to the present day the logical and scientific faction within analytic philosophy has preferred to appeal to Carnap and has its difficulties with Wittgenstein. It is the logical tradition of propositionalism that binds knowledge to the (true) proposition and causes the methodical function of forms of presentation to be misunderstood.
The logic taken as a basis by both Wittgenstein and Carnap is the propositional and predicate logic developed by G. Frege in his Begriffsschrift. In this logic the traditional subject-object structure of propositions is replaced by an argument-function structure, through which a completely new and far-reaching analysis of language is made possible. Within the framework of such an analysis Frege had in particular proposed a logical distinction between four categorially different uses of the verb 'to be': predication (subsumption), identity, subordination (of concepts) and existence.
Carnap makes use of these distinctions in his criticism of Heidegger. In doing so he presents some exemplary sentences of Heidegger's, which — so as to heighten the rhetorical 'effect' — are contracted into the following passage:
"What is to be investigated is being only and — nothing else; being alone and further — nothing; solely being, and beyond being — nothing. What about this Nothing? ... Does the Nothing exist only because the Not, i.e. the Negation, exists? Or is it the other way around? Does Negation and the Not exist only because the Nothing exists? ... We assert: the Nothing is prior to the Not and the Negation. ... Where do we seek the Nothing? How do we find the Nothing? ... We know the Nothing. ... Anxiety reveals the Nothing. ... That for which and because of which we were anxious, was 'really' — nothing. Indeed: the Nothing itself — as such — was present. ... What about this Nothing? — The Nothing itself nothings." (Carnap 1959, 69)
In Carnap's view, Heidegger makes the logical mistake "of employing the word 'nothing' as a noun (Gegenstandsname), because it is customary in ordinary language to use it in this form in order to construct a negative existential statement" (ibid., 70). The negative existential statement 'It is not the case that there exists something which has a certain property' is also expressed by the sentence that nothing has this property. It is through the objectification of this use of 'nothing' that the meaningless talk of 'the nothing' comes about. Part of the responsibility for this lies in the confusion of the uses of 'to be' in the sense of predication and in the sense of existence.
Now Carnap in no way fails to recognize that something important can be addressed in metaphysics. He disputes, however, that it can be represented in the form of meaningful statements. Apart from this Carnap admits that language still has functions other than making statements. Alongside a cognitive function it assumes an emotional one. This serves in particular to give expression of the attitude towards life (Ausdruck des Lebensgefühls). It is in precisely this function that Carnap sees metaphysics, which, however, attempts to clothe something in the form of statements that cannot be said. A legitimate need underlies metaphysics, however, the adequate expression of the attitude towards life is not metaphysics, but art:
"[I]n the case of metaphysics we find this situation: through the form of its works it pretends to be something that it is not. The form in question is that of a system of statements which are apparently related as premises and conclusions, that is, the form of a theory. [...] The metaphysician believes that he travels in territory in which truth and falsehood are at stake. In reality, however, he has not asserted anything, but only expressed something, like an artist." (Carnap 1959, 79)
As the historical source for his surrogate thesis ("Metaphysicians are musicians without musical ability.") Carnap adduces Nietzsche, as that metaphysician, "who perhaps had artistic talent to the highest degree" (ibid., 80) and was hence able to give expression to the Lebensgefühl in the form of poetry (in Zarathustra). At this point a surprising contiguity shows up between the positions of Carnap and Heidegger that leads us back to the theme of forms of presentation.
If we consider the historical stock of philosophical forms of presentation, we find the complete spectrum between the poles of science and poetry. The question is always to which does one orient oneself. Carnap orients himself methodically towards science, that is, towards the justification of statements. With him philosophy is absorbed by the logic of science; it no longer has contents of its own. These contents are passed onto poetry where they find the form appropriate to them. With Carnap, so to speak, Frege's Begriffsschrift lies on the desk and Nietzsche's Zarathustra on the bedside table. For the intermediate form of a "concept-poetry" (Begriffsdichtung in the sense of F. A. Lange) there is no place on either. The result is a problematic dichotomy of cognition and feeling. Apart from this dichotomous accentuation Heidegger seems to proceed from the same finding of a conflict between the form and content of metaphysics. But since it is the contents that matter to him, he departs from the scientific form and consistently approaches (as Nietzsche did) the form of poetry. Carnap and Heidegger, as well as the philosophical traditions founded by the two, have a common point of departure, but proceed from there in opposite directions and thus arrive at diametrically contrary forms of philosophy.
What Carnap announces in 'The Elimination of Metaphysics' (Carnap 1959, 62), namely a detailed exposition of a "metalogical" theory of syntactically meaningful languages, is presented by him in The Logical Syntax of Language (Carnap 1934, 1967). It should be noted that this exposition of the (later) so-called "linguistic framework" represents a transformation of traditional category theories along the lines of the linguistic turn. Whereas in Aristotle we are concerned with categories of being, and in Kant with categories of thinking, the analyses of analytic philosophy of language pertain to the categories of language. Considered in terms of philosophical history, the following line of development results: ontology – epistemology – philosophy of language. Carnap's analyses differ from related endeavours within analytic philosophy in that they do not lead to the establishment of a single categorial framework, but conceive of different frameworks as being theoretically possible.
In the course of its development — starting with Der Logische Aufbau der Welt (Carnap 1928) via Die logische Syntax der Sprache (Carnap 1934) through to Meaning and Necessity (Carnap 1956) — there were indeed shifts in accentuation in Carnap's thinking, namely from a more epistemological (in the sense of Neo-Kantianism), via a formal logical, through to a semantic analysis, but an attitude which Carnap (1934, 44f.; 1967, 51f.) himself formulated as his "principle of tolerance" prevailed constantly. This attitude is characterized by a conventionalist apprehension of languages within the framework of the theory of science.
Carnap also spoke later of the "principle of conventionality of language forms" (Carnap 1963, 55). The basic idea lies in resolving scientific-theoretical disputes over content, such as the foundational dispute between logicists and intuitionalists in mathematics, through the description of different language forms:
"In logic, there are no morals. Everyone is at liberty to build up his own logic, i. e. his own form of language, as he wishes. All that is required of him is that, if he wishes to discuss it, he must state his methods clearly, and give syntactical rules instead of philosophical arguments." (Carnap 1967, 52)
The principle of tolerance is thus part of Carnap's endeavour to eliminate so-called metaphysical "pseudo-problems" from the sciences. It formulates a metatheoretical standpoint which amounts to replacing ontology with logical syntax.
Carnap also applied the principle of tolerance in modified form to the dispute between nominalists and Platonists in semantics. In doing so he distinguished between "internal" questions of existence that must be answered relative to a specific language form (a "linguistic framework") and "external" questions of existence that are concerned with reality as such. External questions of existence continued for him to be pseudo-problems, whereas with admitting language forms that provide the framework for internal questions of existence he recommended the principle of tolerance. The criterion for the admission of linguistic forms was to be scientific utility alone (Carnap 1950; 1956).
Carnap's distinction between internal and external questions, which has Kantian roots, has for a long time not been taken seriously enough in analytic philosophy.8 This is shown by the discussions of scientific realism which are troubled by not having distinguished (from the beginning) between internal and external realism. Yet Carnap had already made clear that science presupposes an internal realism — an empirical realism in the Kantian sense — but that every attempt to found, inductively as it were, an external metaphysical realism on a scientific basis is an impossible undertaking, because it involves a transcendent use of experience.9 The analytic students did not understand their teacher's continental inheritance.
If, for a moment, one ignores the fact that Carnap restricts philosophy from the outset to the explication of scientific language forms, then one could say that he is in agreement with Heidegger at least in the criticism of the presence-at-hand ontology; he adheres, however, to a presence-at-hand syntax.
The subject of language forms is the key to understanding the conflict between Carnap and Heidegger. With the rejection of certain language forms the expressive possibilities of philosophy are curtailed. Carnap acts tolerant, but his tolerance extends only so far as it is possible to translate the language form into a logical syntax. He accuses Heidegger of adopting "many pecularities of the Hegelian idiom (Sprachform) along with their logical faults" (Carnap 1959, 75). Heidegger reacted to this objection in his "Epilogue to What is Metaphysics?'. His answer shows that he had understood the point precisely.
"The suspicion against 'logic', of which logistics10 may be considered a consistently developed degeneration, emerges from the knowledge of that thinking which finds its source in the experience of the truth of Being [Sein], but not in the consideration of the objectivity of the being [des Seienden]. Exact thinking is never the strictest thinking [...]." (Heidegger 1976a, 308)
Heidegger denies the logic oriented towards propositional thinking the right to establish logical linguistic forms as the possible forms of thought altogether. He sees metaphysics as being at work precisely in logistics, and this in the sense of an objectual presence-at-hand ontology. (With his self-critique in the Philosophical Investigations of the one-sided ontology of objects in the Tractatus, Wittgenstein later agreed with him indirectly.) Even though Heidegger has a different metaphysics from Carnap in mind, he too is concerned with an "Überwindung of metaphysics" (he uses this formulation several times). Yet he does not want to eliminate metaphysics, he wants to overcome it. Heidegger wants to direct thinking away from the question of being as the being (Seiendes) towards the question of Being (Sein) itself (Heidegger 1976b, esp. 367f.).
The comparison of Heidegger and Carnap ought to have made clear that the difference between continental and analytic philosophy is above all a matter of the style of thought which manifests in linguistic style. The linguistic style is a matter of rhetoric, and it is not difficult to distinguish authors according as to whether their rhetoric orients itself towards poetry or logic. Such an orientation is not simply a matter of personal taste, rather the apprehension of philosophy itself comes to bear therein — namely as to whether poetic metaphors or logical analysis take on the guiding function in philosophical speech.
It remains to be asked whether analytic and continental philosophy can be 'reconciled' with one another against the background of their shared past. What is meant by this cannot be a colorful 'postmodern' mixture of styles, or even the levelling of the differences existing between the forms of presentation. What matters far more is a thorough analysis of the respective peculiarities from the point of view of their functions. If the one-sided orientation towards the logic of linguistic forms could be overcome and extended in favour of a more comprehensive rhetorics of linguistic forms, then the distinction between analytic and continental philosophy will prove to be historically explicable, but systematically mistaken. For the time being, however, something would already have been gained if the 'fears of contact' were broken down further. In this spirit I would like to conclude by bringing out some elements of continental thinking with Carnap.
If one takes Kant's understanding of metaphysics as a basis, then the appropriate place for the metaphysical ideas (of Freedom, God, and Immortality) is in practical philosophy. Such a shift in location is also undertaken by Carnap in that he traces the theoretical hypostasizations of metaphysics back to practical needs. Carnap's moral point of view is comparable to that of a Kantian socialism, as had been developed in the Marburg Neo-Kantianism. The essential difference lies in that, for Carnap, there is no practical reason which could do justice to this need discursively. To this extent he follows Nietzsche. Morality without justifiability amounts to moral decisionism.
We are, however, also involved with practical, albeit not morally practical, decisions in the approach to the sciences. Carnap's best known example is the decision between idealism and realism (in the question of the existence of an external world), which is classified only as theoretically, but not as practically irrelevant. Carnap also deals with other metaphysical questions in this way. At the official theoretical front door of his philosophy he turns them away, but at the same time he keeps open a back door to the courtyard of practical decision making. This theory-practice dualism is the result of his 'crossing' of Neo-Kantianism and life-philosophy.11
The influence of Kant shows itself with Carnap not only in the adoption of several distinctions (such as those between genesis and validity, and between analytic and synthetic statements), but also in matters of theory construction. Carnap was very well aware that the development of scientific theories takes place from the points of view of unity and fruitfulness (Kant's Zweckmäßigkeit). Such points of view are, however, external in kind. The metaphysical suspicion must then apply to them too. Here once more Carnap backs out of the difficulties by declaring these matters to be practical ones relating to application.
As we have already seen, Carnap uses the expression 'metaphysics' in a somewhat indeterminate manner. In doing so he refers to authors and questions as examples and not generally to everything that has been traditionally counted as metaphysics. In a remark to the English text of 'The Elimination of Metaphysics' he notes that the expression 'metaphysics' is used "for the field of alleged knowledge of the essence of things which transcends the realm of empirically founded, inductive science. Metaphysics in this sense includes systems like those of Fichte, Schelling, Hegel, Bergson, Heidegger. But it does not include endeavors towards a synthesis and generalization of the results of the various sciences." (Carnap 1959, 80) With the addition (in the last sentence), the regulative epistemological function (in the Kantian sense) of metaphysical ideas is obviously being addressed.
A. Naess has rightly noted that, despite the life-philosophical reinterpretation of the concern of metaphysics, Carnap and Dilthey have one thing in common with the metaphysical systems: "They are 'totalizing' views of reality, in Dilthey's sense; they 'set' certain values and represent decisions." (Naess 1968, 46) Last but not least, this is already expressed linguistically in the programme of a "scientific Weltauffassung". The replacement of the Diltheyan expression Weltanschauung (cf. Carnap 1959, 79) with Weltauffassung is nothing more than a word-political measure.12 The difficulty remains of determining how the categorial discourse is to be understood that attempts to speak in a "totalizing" manner about the whole of meaningful language and is hence compelled to go beyond the bounds which it determines as being such. It does not have to become 'poetic' for this reason alone, but it will not be able to abstain from metaphors and other 'rhetorical' forms of presentation. With this philosophy has at least one foot in the poetry camp, it is concept-poetry. It is at this point, I think, that the discussion between Carnap and Heidegger, between analytic and continental philosophy is to be taken up once again.
Translated by Andrew Inkpin
Carnap, R. 1928. Der logische Aufbau der Welt. Berlin: Weltkreis-Verlag. 2nd edition, Hamburg: Meiner 1961.
—. 1931. "Überwindung der Metaphysik durch logische Analyse der Sprache". Erkenntnis 2: 220-241.
—. 1934. Logische Syntax der Sprache. Vienna: Julius Springer.
—. 1950. "Empiricism, Semantics, and Ontology". Revue Internationale de Philosophie 4: 20-40. Reprinted in Carnap 1956, pp. 205-221.
—. 1956. Meaning and Necessity. 2nd edition, Chicago: University of Chicago Press.
—. 1959. "The Elimination of Metaphysics Through Logical Analysis of Language". In: A. J. Ayer, ed., Logical Positivism. Glencoe, Ill.: The Free Press, pp. 60-81. Translation of Carnap 1931.
—.1963. "Intellectual Autobiography". In P. A. Schilpp, ed., The Philosophy of Rudolf Carnap. The Library of Living Philosophers, vol. 11. La Salle, Ill.: Open Court, pp. 1-84.
—. 1967. The Logical Syntax of Language. 7th impression, London: Routledge & Kegan Paul.
Friedman, M. 1996. "Overcoming Metaphysics: Carnap and Heidegger". In R. N. Giere and A. W. Richardson, eds., Origins of Logical Empiricism. Minneapolis and London: University of Minnesota Press (=Minnesota Studies in the Philosophy of Science, vol. XVI), pp. 45-79.
—. 2000. A Parting of the Ways. Carnap, Cassirer, and Heidegger. Chicago and La Salle, Ill.: Open Court.
Gabriel, G. 2002. "Frege, Lotze, and the Continental Roots of Early Analytic Philosophy". In E. H. Reck, ed., From Frege to Wittgenstein. Perspectives on Early Analytic Philosophy. Oxford: University Press, pp. 39-51.
Heidegger, M. 1912. "Neuere Forschungen über Logik". In Frühe Schriften (Gesamtausgabe, vol. 1). Frankfurt am Main: Klostermann 1978, pp. 17-43.
—. 1929. Was ist Metaphysik? Bonn: Friedrich Cohen. In Wegmarken (Gesamtausgabe, vol. 9). Frankfurt am Main: Klostermann 1976, pp. 109-122.
—. 1976a. Afterword to: Was ist Metaphysik? In Wegmarken (Gesamtausgabe, vol. 9), Frankfurt am Main: Klostermann, pp. 303-312.
—. 1976b. Introduction to: Was ist Metaphysik? In Wegmarken (Gesamtausgabe, vol. 9). Frankfurt am Main: Klostermann, pp. 365-383.
Kambartel, F. 1968. Erfahrung und Struktur. Bausteine zu einer Kritik des Empirismus und Formalismus. Frankfurt am Main: Suhrkamp.
Klein, C. 2000. Konventionalismus und Realismus. Zur erkenntnistheoretischen Relevanz der empirischen Unterbestimmtheit von Theorien. Paderborn: mentis.
Krauth, L. 1970. Die Philosophie Carnaps. Vienna and New York: Springer.
Naess, A. 1968. Four Modern Philosophers: Carnap, Wittgenstein, Heidegger, Sartre. Chicago and London: The University of Chicago Press.
Norton, B. G. 1977. Linguistic Frameworks and Ontology. A Re-Examination of Carnap's Metaphilosophy. The Hague, New York, and Paris: Mouton.
Parrini, P. 1994. "With Carnap, Beyond Carnap: Metaphysics, Science, and the Realism/Instrumentalism Controversy". In W. Salmon and G. Wolters, eds., Logic, Language, and the Structure of Scientific Theories. Proceedings of the Carnap-Reichenbach Centennial, University of Konstanz, 21-24 May 1991. Pittsburgh and Konstanz: University of Pittsburgh Press and Universitätsverlag Konstanz, pp. 255-277.
Patzig, G. 1966. Afterword to Carnap, Scheinprobleme in der Philosophie. Frankfurt am Main: Suhrkamp, pp. 85-136.
Rentsch, T. 1985. Heidegger und Wittgenstein. Existential- und Sprachanalysen zu den Grundlagen philosophischer Anthropologie. Stuttgart: Klett-Kotta.
Richardson, A. W. 1998. Carnap's Construction of the World. The Aufbau and the Emergence of Logical Empiricism. Cambridge: University Press.
Stadler, F. 1997. Studien zum Wiener Kreis. Ursprung, Entwicklung und Wirkung des Logischen Empirismus im Kontext. Frankfurt am Main: Suhrkamp.