For G a closed subgroup of S ∞ , we provide a precise combinatorial characterization of when the universal minimal flow M (G) is metrizable. In particular, each such instance fits into the framework of metrizable flows developed in [KPT] and [NVT]; as a consequence, each G with metrizable universal minimal flow has the generic point property, i.e. every minimal G-flow has a point whose orbit is comeager. This solves the Generic Point Problem raised in [AKL] for closed subgroups of S ∞ . space of structures of the form K, < , where < is a linear ordering of N. We endow X K LO with the topology whose basic open neighborhoods are of the form N (L) = { K, < ∈ X K LO : <| [k] = L}, where L is some linear ordering of [k] = {1, 2, ..., k}. With this topology, X K LO is compact and metrizable. We let G act on X K LO via K, < · g = K, < g where (m < g n) iff (g(m) < g(n)). This turns X K LO into a G-flow. When K is a Fraïssé structure, < 0 ∈ X K LO with K,

Social scientists use many different methods, and there are often substantial disagreements about which method is appropriate for a given research question. In response to this uncertainty about the relative merits of different methods, W. E. B. Du Bois advocated for and applied "methodological triangulation". This is to use multiple methods simultaneously in the belief that, where one is uncertain about the reliability of any given method, if multiple methods yield the same answer that answer is confirmed more strongly than it could have been by any single method. Against this, methodological purists believe that one should choose a single appropriate method and stick with it. Using tools from voting theory, we show Du Boisian methodological triangulation to be more likely to yield the correct answer than purism, assuming the Thanks to Natalie Ashton, Seamus Bradley, Clark Glymour, Chike Jeffers, Aidan Kestigian, Erich Kummerfeld, Christian List, Wendy Parker, Kevin Zollman, two anonymous reviewers, and audiences in Munich and London for helpful comments. RH and LKB acknowledge support from the National Science Foundation through grant SES 1254291. RH also acknowledges support from the Leverhulme Trust and the Isaac Newton Trust through an Early Career Fellowship. 123Synthese scientist is subject to some degree of diffidence about the relative merits of the various methods. This holds even when in fact only one of the methods is appropriate for the given research question.

We consider Fraïssé structures whose objects have finite big Ramsey degree and ask what consequences this has for the dynamics of the automorphism group. Motivated by a theorem of D. Devlin about the partition properties of the rationals, we define the notion of a big Ramsey structure, a single structure which codes the big Ramsey degrees of a given Fraïssé structure. This in turn leads to the definition of a completion flow ; we show that if a Fraïssé structure admits a big Ramsey structure, then the automorphism group admits a unique universal completion flow. We also discuss the problem of when big Ramsey structures exist and explore connections to the notion of oscillation stability defined by Kechris, Pestov, and Todorčević [10]. Introduction, main definitions, and statements of theoremsConsider the statement of Ramsey's theorem: for every k, r < ω, we have ω → (ω) k r This "arrow notation" is shorthand for the following statement: for any coloring γ :[ω] k → r, there is an infinite S ⊆ ω so that |γ"([S] k )| = 1. We often say that S is monochromatic for γ. Ramsey's theorem can be generalized in many directions. Erdős and Rado [4] considered coloring finite tuples from larger cardinals while demanding larger monochromatic sets. Galvin and Prikry [7], and later Ellentuck [3], considered suitably definable colorings of the infinite subsets of ω. The generalization that we will consider in this paper is that of structural Ramsey theory. As a warmup, we will consider the structure Q, ≤ of rationals and their linear order. In what follows we will just write Q. Let us call a subset S ⊆ Q a dense linear order, or DLO for short, if the ordering on S inherited from Q is dense and contains no maximum or 2010 Mathematics Subject Classification. Primary: 22F50; Secondary: 03C15, 03E02, 03E75, 05D10, 37B20, 54D80, 54H20.