Various forms of “pluralism” are making the rounds these days. There is, for instance, the “logical pluralism” of Beall and Restall (among others), the subject of a recent book by Stewart Shapiro, which will be discussed here at some point. But then there is also something much vaguer and murkier called “ontological pluralism,” which, amazingly, is attributed to Carnap. Matti Eklund, for instance, considers this question in his paper in the Metametaphysics volume. What does he mean by it? He considers various formulations, starting with the “quantifier-variance” understanding of Hirsch, in which ontological pluralism requires the quantifiers to take on different interpretations in different languages. But Eklund thinks this is insufficiently precise, as it can seem to amount to “the thesis that a string of symbols can come out true in some languages but false in others, while meaning what it actually means.” The trouble with this, he thinks, is that it “would appear to commit the ontological pluralist to a form of relativism or idealism absent from pluralist writings.” (p. 138)
The quantifier-variance interpretation of Carnap doesn’t get off the ground, though, because Carnap does not see the quantifiers in the different possible external statements as having different interpretations; he sees them as having no interpretation at all. This also extinguishes Eklund’s further worry, quoted at the end of the above paragraph, since Carnap did not think truth or falsehood had any application in external discourse; they could be applied only with respect to an explicitly specified descriptive language. And what a sentence “actually means” is of course entirely language-relative. So it is not “the same sentence” in different languages. A “string of symbols” cannot “come out true in some languages but false in others, while meaning what it actually means,” because “what it actually means” is not specifiable language-independently. To suppose that a string of symbols “actually” means something independently of the language it is expressed in is just to take an external statement literally, at face value.
To even consider attributing this to Carnap betrays a failure to grasp the most fundamental feature of Carnap’s later philosophy, i.e. the specifically Carnapian linguistic turn I’ve discussed elsewhere. Fans of ontology should by all means go off into their ivory-tower “ontology room” and study “ontological pluralism” to their heart’s content. But could they please stop associating it in any way with Carnap?
Hello André, here is a more worked out version of my comment: https://terenceblake.wordpress.com/2015/05/31/carnap-and-ontological-pluralism/. I think I have gone off on a tangent, and perhaps mis-represented you. If so I will amend my text. Cheers, and thanks for an inspiring blog.
Hello André, I defend a realist ontological pluralism, and take care to dissociate it from relativism. So I guess I am reacting to a side point to your main argument, but I do not see why you are so mocking of this position. I find it developped in the later Feyerabend, who was certainly influenced by Carnap, amongst many others. So if Carnap was never an ontological pluralist, this is a good point to make. But it is not necessarily something to be proud of. Here I am surprised to find you resembling the grumpy Wittgenstein rejecting Esperanto, despite you having published Carnap’s reply to such an attitude elsewhere on your blog. Bruno Latour is another ontological pluralist, but his philosophy does not resemble “postmodern” silliness. Gilles Deleuze is another (in my interpretation of his work). So I thank you for your references to Beall, Restall, and Shapiro, as I have never heard of them.
I was also shocked by your rhetoric of the “ivory tower”. What’s so wrong with ivory towers? A blog is an ivory tower, and my blog is an ivory tower edified to the glory of epistemological and ontological pluralism. You too have a blog, a Carnapian ivory tower. I have read all your posts and I see therein no solution to global warming or to high cost of health care. This is no objection, as solving this sort of thing is not in the specifications of this blog. No doubt a better knowledge and understanding of Carnap could well help our thinking about these and other practical matters, but that is another matter. One thing that emerges from your portrait of Carnap is that he was concerned with practical matters, but he had no shame of intellectuality as such.
I have no objection whatever to ivory towers, nor did Carnap, as far as I know. In fact I think the contemplative life has become an unfortunate casualty of certain institutional developments in response to, most recently, the internet and associated technologies; I am all in favor of the Glasperlenspiel, but have no more idea how to clear a space for it in our current mode of life than anyone else does. I am appalled at the complacency with which it’s been largely accepted worldwide that the essential function of higher education is to invest in human capital, with the traditional function of enlightenment and “liberal education” largely forgotten. I see how the final sentence of this post could be interpreted as sarcasm, but I meant it literally: if they want to go do that, fine, but leave Carnap out of it. The “ontology room” is Chalmers’s term, not mine; I’ve complained about the disconnection between his “ontology room” and anything else in life elsewhere. Ivory towers I’m all in favor of, but the rarefied things going on there should have some substance, and I’m not persuaded (for the reasons given in that post and its predecessors) that the new metaontology is going much of anywhere.
As for ontology more generally, I basically share Carnap’s attitude in ESO; I don’t see the point of it unless we reinterpret metaphysical choices as choices among languages. There are plenty of praiseworthy and even heroic things being done under the heading of ontology, such as Barry Smith‘s efforts to combat bureaucratic incompetence in the construction of biomedical databases. This is important work and I’m glad someone is doing it. But Carnap wouldn’t have called that ontology, he’d have called it semantics. He would also have admitted that the philosophical prejudices underlying the practical activity probably won’t make that much of a difference to the outcome. I still think it’s worth trying to understand ourselves and what we’re doing, so I will persist in arguing for my Carnapian prejudices and seeing where they go.