One might wonder why a social ontologist should care about metametaphysics and read an introduction to the topic such as the one written by Tuomas E. Tahko.
Answering the question requires to take stance on some substantial disputes about social ontology and its methods. Before making some of these general remarks, let us focus on the book.
Tahko’s Introduction, though not interested in historical questions, follows a chronological order in presenting the topics of metametaphysics. After an introduction on why we should care about metametaphysics (ch. 1), we start with the Carnap-Quine debate (ch. 2) before focusing on ontological commitment and its alternatives (ch. 3). These chapters allow us to distinguish the three main positions in the contemporary metametaphysics debate (ch. 4): Quiniean views, Neo-Aristotelian views, and deflationists views – further divided along the realist vs. anti-realist axis.
After setting the stage and explaining how we arrived at the current state of the art, the book presents the main contemporary topics of metametaphysics: grounding and ontological dependence (ch. 5), levels of reality and fundamentality (ch. 6).
Then the book adds something in the last three chapters to the standard view of (meta)metaphysics, as Tahko is convinced that some (modal) epistemological issues are deeply entrenched with metametaphysics. The issues discussed are the status – a priori or a posteriori? – of metaphysics (ch. 7), the role of intuitions and thought experiments in metaphysics (ch. 8) and the relationships between metaphysics and science (ch. 9).
A clearly written glossary, a bibliography and indexes (names and concepts) finish the volume, which targets both graduate students and experts in philosophy whose main interests lie outside metametaphysics.
Now it is time to get into the book and produce some spoilers about it. First, the book is written by a Neo-Aristotelian: Tahko is clear in stating his background credo but struggles to remain neutral in presenting the issues. His background can be detected more by what he chooses to present rather than by how he discusses the topics: given a debate, he carefully presents all the leading figures and positions.
A strategy I have appreciated in the book is that, after presenting the main positions and issues of a debate in general, Tahko dives into a more specific topic taking it as a case study. For example: Varzi is discussed as an example of conventionalism, Sider is a case-study for ontological realism and Hirsch for quantifiers variance. That is a great strategy to avoid students having just a big picture of “-isms” with nothing substantial attached to them.
Throughout the book, some examples from physics will pop out in different discussions. Physics investigates the fundamental levels of reality, hence Tahko thinks it is a good benchmark for every metaphysical position that addresses issues in fundamentality. The topics from physics will go beyond gold and its atomic number of 79 or electrons. Fermions, the EPR experiment, the Copenhagen interpretation, the standard model, Pauli’s exclusion principle, the Bose-Einstein condensate and more shall all be there. But fear not, all these topics are introduced in a way that makes them accessible to the non-physicists and Tahko readily points out the philosophical significance of the physics he mentions.
Many issues resonate to a social ontologist while reading the book, especially in chs. 5-6. Grounding, dependence and mereology can help the social ontologist in many ways. The Searlean question of going from electrons to elections can be fruitfully investigated as a question of ontological dependence and grounding which are tools we can use to better explain how brute facts feature in institutional facts. 
Mereology plus dependence shall also help us laying down existence conditions for groups and other collective entities, though probably game theory is still the more popular tool to explain how groups interacts and reasons.
Getting a more into details (arbitrarily chosen), I will focus on two points closely connected to social ontology. The first is the discussion of extreme conventionalism. Varzi’s paper is a great example to present extreme conventionalist’s logic and some of its problems. My worry is that, as in other writings Varzi defends a Quineian view of ontology and Universalism in mereology: the book’s presentation might lead students to place him in a box (extreme conventionalism) that does not fully represent him. For sure there is a tension between these two sides of Varzi, as Varzi himself acknowledged in another paper (Varzi 2014). Such a tension is worth pointing out here in this review as it looks familiar for the social ontologist: social entities are intrinsically dependent on social practices and institutions (the conventional part of Varzi’s story), yet they are entities and they exist (the universalist part of Varzi that takes quantifiers and ontological commitments seriously).
The second point is related to the prehistory of metametaphysics as we know it today and concerns ontological commitment.
It is worth noting that one of the most discussed philosophers in social ontology, John Searle, entered one of the first debates on ontological commitments. In his Speech Acts, (Searle 1969, p. 5.3) he offers a “reduction” of (Quineian) ontological commitment (Searle draws in part on the work of Church and Alston of late 50’s). Such a discussion is omitted in Tahko’s book, I think both for space reasons and for his aiming to present the live issues and the contemporary state of the art debates (by the way, it is worth noting that Searle’s paragraph has not been discussed in deep by social ontologists).
One of the things we learn from Tahko’s book is that there is no need to follow Quine in defining criteria of ontological commitment, but if we want to do some serious ontology, we have to deal with this problem, not simply dismiss it. Tahko’s book helps us unveiling one of the paradoxes of social ontology: it is an ontological discipline that, at least according to its Searlean form, has no interest whatsoever in ontology(cal commitment).
The field of social ontology is interdisciplinary: game theory matters, the impact of cognitive sciences and sociology is huge. If we make room for meta-metaphysics in social ontology, we would be able to clarify the “ontology part” of social ontology. Those who, following Barry Smith, argue that in Searlean social ontology we lack some heavy-weight ontology, will find in the book a great companion of the wonderful but forgotten things that ontology and metaphysics offer to social ontology.
If you think social ontology has to be kept Searlean and uninformed about other ontological and metaphysical concepts, reading an introduction to meta-metaphysics allows you to invest your time in a wise manner as you will quickly to get to know your enemy. 
Epstein, Brian (2015): The Ant Trap. Oxford: Oxford University Press. Search in Google Scholar
Searle, John R. (1969): Speech Acts: An Essay in the Philosophy of Language. Cambridge: Cambridge University Press. Search in Google Scholar
Thomasson, Amie L. (2015): Ontology Made Easy. Oxford: Oxford University Press. Search in Google Scholar
Varzi, Achille C. (2014): “Counting and Countenancing”. In: Donald Baxter and Aaron Cotnoir (Eds.): Composition as Identity. Oxford: Oxford University Press, pp. 47–69. Search in Google Scholar
©2017, Guglielmo Feis, published by De Gruyter.
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.