Recently, many philosophers and historians attempted to show how Rudolf Carnap’s project still has relevance in post-positivist philosophy. A second, somewhat independent, trend focuses on methodological issues in ontology (‘metaontology’). This literature seeks to understand what epistemic status ontological claims have and what kind of claims about the world can be considered genuinely meaningful. The 11 papers in Ontology After Carnap (‘OAC’) (eds. Stephan Blatti and Sandra Lapointe) adds to these trends by revisiting some of Carnap’s overlooked insights and their relevance for contemporary metaontological disputes. In the same way that we continue to learn from Plato and Aristotle 2,500 years later, it is increasingly apparent that the depth of Carnap’s thought hasn’t been exhausted quite yet.
Conventional wisdom in the history of analytic philosophy and philosophy of science is that the positivist movement has been shown to be fundamentally flawed by Quine’s famed criticism of analyticity in ‘Two Dogmas.’ Analyticity played a central role in the distinction between observational and theoretical terms, forming the basis of their epistemology and their analysis of mathematical knowledge. The inability to formulate a non-circular definition of analyticity led to positivisms’ downfall. Efforts were made to salvage what remained and make some form of empiricism tenable but, by and large, positivism became a historical stepping stone to more sophisticated epistemologies.
OAC attempts to demonstrate what insights can be retained from Carnap post-Quine. Specifically, the use of analyticity in Carnap’s landmark “Empiricism, Semantics and Ontology” (1950) (‘ESO’) is highly useful in addressing issues in metaontology. In ESO, Carnap devises the notion of a ‘linguistic framework’, a purely formal notion with two features: axioms and correspondence rules. The axioms can be either analytic statements (e.g., ‘The mass of a body is equivalent to its quantity of matter’) or synthetic (e.g., Newton’s third law of motion) which provide the rules for forming meaningful propositions within a framework. The correspondence rules (rules of syntax) ‘connect’ these axioms to observational propositions. Combining a linguistic framework with experience gives a meaningful way of speaking about the world (see Alan Sidelle’s contribution (60-9)). Carnap’s primary contribution in this article is his conception of the relationship between ontological questions and linguistic frameworks. Traditional ontological questions concern what exists; what sort of things make up the furniture of the cosmos. Do physical objects exist? How about numbers? Laws? For Carnap, there are two ways that these questions can be asked: as internal or external questions. Internal questions treat questions of ‘what exists’ as relative to a framework. They can be answered trivially by checking the analytic terms of some framework. Do electrons exist? According to electromagnetism, yes! Do demons exist? According to medieval medicine and psychology, yes! According to contemporary Western psychiatry, no! While these questions are often empirically difficult to answer, philosophically speaking, the answer is quite mundane. However, according to Carnap, this is not how traditional metaphysics conceived its questions; they considered them as external questions. External questions do not merely ask what exists relative to some framework but about what exists independently of all frameworks. For Carnap, these questions can only be understood as pragmatic questions about which framework to adopt (to be judged by criteria of fruitfulness, expediency, etc.) and not factual questions. What really exists, independent of some linguistic framework, is a confused and meaningless pseudo-question. This distinction between internal and external questions (‘I/E distinction’) is one of the main themes of OAC.
Many of the contributors to this volume express differing views about the I/E distinction. In Thomas Hofweber’s contribution, “Carnap’s Big Idea” (the ‘big idea’ being the I/E distinction), he argues that Carnap’s defense of the I/E distinction is problematic. This is because questions like ‘Are there numbers?’ can be interpreted not just as internal or external questions, but in a wide variety of ways depending on their utterance. He then defends the I/E on independent grounds, arguing that there are two readings of quantifiers in ordinary language (the inferential reading where ‘Something is F’ is true if there is a F(t) in that language and the domain reading where ‘Something is F’ is true if some extra-linguistic F exists), which have distinct inferential capacities, and closely parallels the I/E distinction. However, the choice of a particular interpretation has no ontological consequences but merely a difference in truth values. I think this view is quite interesting, although I think the I/E distinction Carnap had in mind was a distinction between kinds of methodological questions rather than kinds of contextualized utterances. Regardless of its historical adequacy, it is an interesting question whether the I/E distinction can be understood in terms of speech acts. If so, as Hofweber notices, then the ‘elimination of metaphysics’ would be largely overstated since many metaphysical speech acts are perfectly ‘meaningful’ (in a non-technical sense) and productive in ordinary contexts. How the I/E distinction maps onto the kinds of questions scientists (and others) actually ask is a fascinating topic deserving of further research.
For a less sympathetic treatment, Matti Eklund’s “Carnap’s Legacy for the Contemporary Metaontological Debate” criticizes the I/E distinction. Eklund argues that there are two ways this distinction can be read and both are problematic. One is the ‘language pluralist’ interpretation. In this view, any existential sentence (that is non-semantically individuated) is a part of many linguistic frameworks and its truth-value is framework-relative. The other reading is the ‘relativist’ interpretation where propositions are true or false relative to some framework. Thus Platonism and nominalism are both genuine frameworks (i.e. express true propositions) whereas they are merely useful language-fragments for the pluralist (see Lavers pg 209, fn. 13 for a criticism of this interpretation). Eklund’s criticism is that pluralism or relativism, taken at face value, cannot deflate ontology talk. He writes “[f]or the envisaged criticism of ontology to be effective it would of course have to be shown that the questions ontologists ask are really confused questions in the sense characterized. It is not clear how plausible this is, or how one may go about arguing the point” (168). He goes on to argue that more contemporary positions on metaontology are largely un-Carnapian and thus his legacy is quite minimal for contemporary discourses. Regardless of the validity of the second argument (for which Blatti and Lapointe must be praised for including in their collection that presupposes the opposite thesis), I think the argument against Carnap’s own view is a bit thin. Eklund acknowledges that the view in ESO is strongly motivated by Carnap’s empiricism and his views on verification (176) but then provides no argument against it (he merely notes that these results would generalize to other areas of philosophy as well). There are, of course, many arguments that could be made here but without addressing the viability of empiricism (a topic which is faintly touched on in OAC) it remains unclear why Eklund rejects the I/E distinction.
Finally, the I/E distinction is given a novel defense (Amie Thomasson’s contribution) and a novel interpretation (Lavers’). Thomasson addresses another of Quine’s arguments against the I/E distinction. Quine’s argument in “On Carnap’s Views on Ontology” (1951), roughly goes like this: the I/E distinction is actually derivative of a more basic distinction between categorical questions (“Are there Fs?” where ‘F’ exhausts the domains ontology) and subclass questions (“What are the boundaries of Fs?”). This distinction, while true, is trivial since it just depends on what variables we assign to what (it is a set of “logically irrelevant changes of typography” (Quine 1951, 210)). More importantly, according to Quine, the distinction makes no difference for ontology. Thomasson notes that the I/E distinction does not dissolve into the category/subclass distinction since internal questions can be both category questions (“Are there numbers?”) and subclass questions (“Are there prime numbers?”). Therefore, this only shows that there are different kinds of internal questions, something Carnap would happily accept. In Lavers’ paper, he argues that ESO should be considered an extension of his notion of ‘explication’ developed in The Logical Foundations of Probability (1950). This concept (which is discussed in a variety of ways throughout OAC, e.g., Biggs and Wilson’s contribution (89-90)), can roughly be understood as this: we often encounter, in the sciences and ordinary discourse, ideas that are vaguely formulated and, therefore, have indefinite truth conditions. In order for these concepts to become inferentially fruitful, they must be formulated in a precise proposition (or set of propositions) and embedded within a linguistic framework. Carnap gives four desiderata for an explication:
- “The explicatum (explicated concept) must be similar to the explicandum (the vague concept) in such a way that, in most cases in which the explicandum has so far been used, the explicatum can be used; however, close similarity is not required and considerable differences are permitted.
- The characterization of the explicatum, that is, the rules of its use….is to be given in an exact form, so as to introduce the explicatum into a well-connected system of scientific concepts.
- The explicatum is to be a fruitful concept, that is, useful for the formulation of many universal statements…
- The explicatum should be as simple as possible [i.e. as the more important requires (1), (2), and (3) permit]” (Carnap 1950, §3).
This view comes in response to classic problems with the traditional view of conceptual analysis (found originally in Plato’s Meno and in more detail in Moore (1899)). Lavers argues that ESO can be read as providing details for how to explicate theoretical frameworks.
I think this argument is quite intriguing and deserves great attention. I want to pause for a moment, though, to consider a difficulty that comes from this notion. In both Lavers’, and Biggs’ and Wilson’s papers, the explicatum replaces the explicandum. This interpretation, which I think is faithful to Carnap, seems to conflict with Carnap’s pragmatic streak. First of all, even when concepts are vague and poorly defined they can be, and often are, fruitful. Even before, say, the Frege-Russell definition of numbers as classes of classes of individuals, arithmetic was making some progress with its vaguely defined explicandum(s). Furthermore, we recognize that the explicatum and the explicandum are different (by definition) and that explicandum can be explicated in a (potentially) indefinite number of ways since concepts evolve and change and can be co-opted at any point in the future. Therefore, it may be pragmatic to keep the explicandum around (either the ‘leftovers’ or the vague concept as a whole) for future uses. In this view, explicatums don’t ‘replace’ anything; they are entirely new concepts that happen to be similar to pre-existing ones! But I digress, since this point does not affect Lavers’ argument as a whole.
Another Carnapian notion explored in OAC is the principle of tolerance. The principle has been understood in numerous ways, but it can basically be understood as an acceptance of any linguistic framework (and any explication within a framework) insofar as it is fruitful. The most detailed discussion is found in Eli Hirsch’s paper “Three Degrees of Carnapian Tolerance” (see also Richard Creath’s contribution (194-201)). While Hirsch is explicit that he is not engaged in Carnap exegesis, the principles he distinguishes are still ‘Carnapian’ in a loose sense. Hirsch endorses the first degree of tolerance and it is central to his view of verbal disputes. This tolerance holds in conditions where we are “merely choosing a language” (105). Hirsch clarifies that the conditions under which we are ‘merely choosing a language’ is when the ‘equivalence condition’ is satisfied. The equivalence condition states that any ‘controversial’ sentence (or inference) is not substantial if there is some sentence in each of the debaters languages into which it can be translated salva veritate. The equivalence condition is sufficient, but not necessary for deflating disputes. Resolving the dispute can be achieved in two ways: by charity (interpreting the opponent as asserting something true in one’s own language) or by stipulation (stating that the controversial sentence is true relative to a language by fiat). Hirsch goes on to make some interesting remarks about the seemingly indefinite rate which new problems arise in ontological disputes and the implications this has for charity and what implications stipulation may have for the phenomenology of ontological debates. Hirsch then goes on to discuss the 3rd degree of tolerance which is equated with verificationism (which Hirsch claims should be ‘shunned’ (117)) and the 2nd degree of tolerance is much more radical than the others since it decrees that one may learn a new ontological language (which divides up the logical space in a new way) and alter one’s ‘coarse grain thoughts’ even when the equivalence condition doesn’t hold. Hirsch argues this is intolerable since it relies on a confusion whether ontological debates are substantive or not. While this distinction is interesting and requires further attention, the main contribution to metaontology here is the novel recasting of Hirsch’s notion of a verbal dispute. Here, Hirsch defends his earlier formulations from the criticism that the notion of a verbal dispute involves a commitment to verificationism (which Hirsch is at pains to avoid). The discussion here, and the variety of criticisms and addendums proposed by other authors in OAC (see Sidelle (66-9), Thomasson (132-142) and Eklund (176-84)) will be of interest to anyone interested in metaontology and ontological deflationism.
Another major issue in metaontology is quantifier variance. Quantifier variance was thrust into mainstream analytic philosophy by Hilary Putnam (see Thomasson (131-4) for a criticism of Putnam’s views). Quantifier variance is an acknowledgement of the vast diversity of senses in which the word ‘exists’ (and its cognates) as well as the polysemous use of the existential quantifier ‘∃x’ (e.g., in second-order logic and category theory). This radically contrasts with Ted Sider and Peter van Inwagen’s views that the meaning of ‘existence’ is univocal and closely related to basic (universal!) rules of arithmetic. Therefore, ∃x carves the world by its logical joints. This argument is central to ontological pluralism and ontological deflationism. Many of the contributors provide different analyses of quantifier variance, all of which are novel and deserving of attention. In Thomasson’s piece, she argues that proponents of ontological deflationism (or ontological pluralism) need not be committed to quantifier variance. Even Carnap’s brand of ontological deflationism, she argues, didn’t rely on the notion at all! Similarly, Hirsch’s view only requires that quantifier variance is possible so the invention of new uses of the term ‘exists’ or ‘∃x’ wouldn’t be ruled out a priori. In Eklund’s paper, he criticizes Hirsch’s view of quantifier variance and says it either relies on the trivial observation that there can be multiple concepts that can be implied by some string of symbols (say, ‘exists’) or the self-contradictory claim that ‘exists’ is both semantically determinate and has multiple meanings. Similarly, Eklund argues against ‘Carnap’s’ view (the scare quotes signify that it isn’t clear that Carnap held a version of the quantifier variance view, see Thomasson (134-7)) that language pluralism must postulate a ‘universal meta-language’ in which the propositions of positivism itself can be meaningfully expressed. While Creath’s paper provides one solution to this view on Carnap’s behalf, it may be worthwhile to point out that this problem is not a new one. Wittgenstein, for example, postulates that philosophy is not a position (i.e. set of propositions) but an activity. In the Tractatus, he writes:
“Philosophy is not a theory but an activity. A philosophical work consists essentially of elucidations. The result of philosophy is not a number of “philosophical propositions,” but to make propositions clear” (Wittgenstein 1921/2001, 77).
“My propositions are elucidatory in this way: he who understands me finally recognizes them as senseless, when he has climbed out through them, on them, over them. (He must so to speak throw away the ladder, after he has climbed up on it.) He must surmount these propositions; then he sees the world rightly. Whereof one cannot speak, thereof one must be silent” (89).
Carnap, in an earlier paper “The Character of Philosophic Problems” (1934), attempts to build on this and provide a positive proposal whereby the propositions of logical empiricism can be understood as either ‘assertions’ (e.g. ‘In language x such and such holds’) or ‘proposals’ (e.g. ‘I propose to construct a language with such and such properties’) (see Carnap 1934, 13-9). I will not delve deeper into this issue, but it should be noted that this problem was well recognized, even amongst the earlier positivists, and there have been proposals to remedy it.
Before making some more general comments about OAC, this review would be bereft without explicitly acknowledging the three papers not discussed thus far. Robert Kraut’s paper “Three Carnap’s on Ontology” surveys a number of possible interpretations of Carnap’s views of ontology and defends the view that Carnap’s was expressivist whereby ontology does not refer to anything, but still expresses some evaluative sentiment. On this view, Carnap does not seek to undermine ontology but merely “portray[s] it as consistent with empiricist epistemological scruples” (31). This is a fascinating and original view. If true, then much of the ‘elimination’ of metaphysics discussed throughout Carnap’s career amounts to much less than expected in terms of practical implications. Rather than trying to formulate imperatives like “Don’t waste time reading and thinking about Leibniz!” or “Ontological intuition is no reason to criticize a scientific theory!”, ontology talk becomes a valued part to scientific practices! Carnap’s pluralism, maybe, extends to a tolerance of fallibilistic ontology itself! Rather than the ‘eliminativist’ view that seems common amongst Carnap admirers (which Kraut explicitly discusses and rejects), Kraut’s interpretation of Carnap may have radical implications for Carnap scholarship and its practical implementation. While Kraut does not use these passages to support this interpretation, it may be worthwhile revisiting some remarks Carnap makes in chapter 1 of Philosophy of Logical Syntax. Here, Carnap explicitly distinguishes between the purported ‘representative’ function of ontology (that ontology-talk describes reality in some sense) and the ‘expressive’ function. He writes “[ontological] propositions in the metaphysical books obviously have an effect on the reader, and sometimes a very strong effect, and therefore they certainly express something” (Carnap 1935, 27) and explicitly acknowledges the potential value of ontology understood expressively. Here, there seems to be additional textual support for Kraut’s interpretation.
Furthermore, while most of the Carnap rehabilitation project has been directed towards Quine’s criticisms, Stephen Biggs and Jessica Wilson’s paper “Carnap, the Necessary A Posteriori, and Metaphysical Anti-Realism” seeks to recuperate a nuanced version of Carnap’s intensionalist semantics in light of Kripke’s criticisms of descriptivism. Here, they propose that a quasi-Carnapian program can be retained if understood as the position they call ‘abductive two-dimensionalism.’ This paper is especially valuable since much of the secondary literature focuses almost exclusively on Quine without acknowledging the vast variety of criticisms launched during the 20th century at Carnap and logical empiricism (for exceptions see Yap 2010 and Uebel 2011). It wasn’t just ‘Two Dogmas’ that led to the deterioration of the program, but the historical schools criticisms (e.g., Kuhn, Polyani, Feyerabend, Lakatos), the criticisms from ordinary language philosophers (e.g. Toulmin, Austin), the criticisms of theory-ladenness (e.g., Hanson, Kuhn, and Feyerabend), induction (e.g. Popper and Hempel), pragmatism (e.g., Sellars) and the subsequent literatures that emerged (e.g., the sociology of scientific knowledge, science and technology studies, feminist criticisms of science). While it remains unclear what can be salvaged of Carnap’s view regarding these criticisms, Biggs and Wilson’s paper implicitly represents a step in the right direction whereby a full rehabilitation must address the large spectrum of concerns that have been raised since the 1950s.
Finally, Kathrin Koslicki’s paper “Questions of Ontology” provides an excellent contrast for the other contributions in OAC. Here, she argues that the focus on ‘ontology’ in metaontology is needlessly shallow and doesn’t address the issue of fundamentality which pervades many metaphysical debates. She provides an analysis of the debate between ‘pure trope theorists’ and ‘impure trope theorists’ where what is at stake is not ontology, since they agree on what exists (e.g. concrete particulars, tropes, causal powers) and what doesn’t (e.g., universals, abstracta, numbers), but disagree about what is fundamental. First off, Blatti and Lapointe should be credited for including a paper which criticizes metaontology for being overly narrow. Second, Koslicki’s remarks open up a wide variety of questions about the scope of ontology and whether these questions can be answered non-metaphysically. Perhaps fundamentality can be simply construed as a set of relations between particulars and thus the working conception of ontology is broad enough to incorporate Koslicki’s observations. I’m not sure where this debate would lead exactly, but it is an important question to know what kind of debates metaontology is meant to address.
OAC largely presupposes the achievements of similar volumes (particularly Chalmers, Manley, and Wasserman’s Metametaphysics) and previous papers on metaontology and Carnap. This work should therefore be viewed as an attempt to clarify and develop these two budding literatures. As a whole, then, OAC will be of great interest for those already interested in debates about Carnap and his contemporary relevance or metaontology. However, a word of caution to Carnap historians: this collection is ambiguous (and occasionally self-contradictory) about whether these papers are meant to be historical or not. In the introduction, Blatti and Lapointe state the papers in this volume (pace Lavers) are not meant to be historical but simply using insights of Carnap for their own purposes. This would be fine, but nearly every paper is peppered with statements like ‘Carnap’s real view is…’, ‘Carnap didn’t think x about y’, ‘So and so is wrong to attribute view x to Carnap…’, etc. Perhaps these are just slips of the tongue, and they should be treated as such (the vast majority of the contributions focus almost exclusively on ESO without contextualizing it within Carnap’s corpus). Regardless of this, Carnap enthusiasts will be thrilled to see how many of his views (on tolerance, explication, the I/E distinction, analyticity, etc.) are being debated and used. The internal disputes within the volume will be of interest to anyone studying metaontology and many views central to the field are made more sophisticated. Additionally, those studying metaphysics itself (or cognate fields like meta-ethics) will be interested in what is being said about their methods. Additionally, while no paper does this explicitly, I think many of these papers have opened up conversations for how metaontology makes a difference to practice. How might our philosophical, scientific, or even social practices be changed as a result of the arguments found in metaontology? I have attempted to point to a few examples where this discussion has begun in OAC in this review (see my comments on Hofweber, Kraut, and Lavers). These questions are of crucial importance to the relevance of these topics to other fields of philosophy and other disciplines altogether. While metaontology and Carnap scholarship may be too young to meet these demands right away, it is something worth keeping in the back of our minds. All in all, OAC provides an excellent overview of a wide variety of contemporary issues with a good dose of healthy disagreement. It is a worthwhile companion to the literatures it seeks to contribute to and I look forward to seeing what directions this field takes in the future.
Carnap, Rudolf. 1934. “On The Character of Philosophic Problems.” Philosophy of Science, 5-19.
Carnap, Rudolf. 1935. Philosophy and Logical Syntax. London: Routledge.
Carnap, Rudolf. 1950. “Empiricism, Semantics, and Ontology.” Revue Internationale de Philosophie, 20-40.
Carnap, Rudolf. 1950. Logical Foundations of Probability. Chicago: University of Chicago Press.
Moore, G. E. 1899. “The Nature of Judgment.” Mind, 8(2), 176-193.
Quine, W. V. O. 1951. “On Carnap’s Views on Ontology.” Philosophical Studies, 2(5), 65-72.
Uebel, Thomas. 2011. “Carnap and Kuhn: On the Relation Between the Logic of Science and the History of Science.” Journal for General Philosophy of Science, 42(1), 129-140.
Wittgenstein, Ludwig. 1921/2001. Tractatus Logico-Philosophicus. London: Routledge.
Yap, Audrey. 2010. “Feminism and Carnap’s Principle of Tolerance.” Hypatia 25(2), 437-454.