Although Ted Sider’s “ontological realism” doesn’t entail that things like ships and frogs are eliminable, this is because he views quantificational structure (where quantification ranges over physical items) as part of the world’s objective structure. Frog-hood and ship-hood then hold of particular objects in virtue of the “fundamental” structure of the world and the specifically Aristotelian idea of enduring substances with real essences is disavowed (in favor of a four-dimensional conception of objects that have proper “temporal parts”).
By contrast David Wiggins (in Sameness and Substance Renewed) denies Sider’s central commitment to the world’s fundamental ontology being physics-plus-logic. (That’s on my reading since I don’t remember Wiggins referencing Sider specifically.) For Wiggins, there is no identity, and no determinate existence claim, prior to a sortal concept supplying criteria of individuation and persistence to an object (or person or organism). So, on Wiggins’s view planets and electrons stand on the same ontological footing as ships and frogs. All continuants are individuated by sortal concepts carrying their own criteria of persistence and individuation, while acknowledging a spectrum between the discovered and the constituted (living kinds at the discovered end, since their principle of activity are most robustly real and least answerable to our purposes while artifacts sit closer to the constituted end. “Planet” may be a nice intermediate as Pluto’s recent redefinition(s) by astronomers illustrates). So you are right that Thompson commits to realism at the level of the life-form, but I’d add that Wiggins gives the general ontology of continuants within which that commitment sits, and it appears Aristotelian in just the sense Sider appears to foreclose.
I think this may connect to @Count_Timothy_von_Icarus’s causal closure worry (that I’ll revisit in more detail at another time). I had suggested that physics discloses the “realm of law” by prescinding from the forms of its objects. But the lesson from pragmatism (and from the new instrumentalism of Ian Hacking and Michel Bitbol) is that it does so while being unable to prescind from the forms of its instruments. Nothing counts as a measurement, and no law-statement gets empirical purchase, unless the apparatus is taken as an apparatus. And an apparatus, as such, is a functionally individuated bit of equipment. That functional form is presupposed by the law-statements, not disclosed by them (Haugeland’s constitutive standards, in Truth and Rule-Following and Pattern and Being, highlight that the dependence stems from our disclosing activity). Niels Bohr has a similar idea. The necessity of “classical language” thesis and the cut between “observed system” and apparatus is the place where a functional description of the arrangement becomes ineliminable. It’s impossible to push the formalism all the way to the pointer (in order to characterise the measurement process quantum mechanically) without losing the ability to say what was measured.
I suggested elsewhere that Bitbol supplies the vocabulary that makes this general (in De l’intérieur du monde, unfortunately not yet translated in English). Physics construes its objects as fully constituted by the laws governing their interactions. These are lateral relations. But those laws are disclosed to us only through our instrumental norms and practices (that include, importantly, our decisions what to abstract from for the sake of generality and at the cost of specificity). Those are transversal relations between us and our world. And this, I think, threatens to leave things like frogs stranded from our ontology, which, interestingly, tells against Bitbol’s own disavowal of Aristotelian substance. The frog looks stranded because we are reading its life-form as a set of lateral facts. But a life-form, on Thompson’s Aristotelian conception, is not a set of lateral facts. It is the transversal principle under which a lateral order (the frog’s affordance-network, its metabolic and behavioural commerce with its Umwelt) is unified and governed. It’s a transversal relation between the frog and its Umwelt.
So the very distinction Bitbol uses to dissolve the substance (the object is “nothing but” its relational role, so there is no bearer of form underneath) is what restores it once one sees that a living thing is not exhausted by any lateral role that it plays in our practices of dealing with it, but rather is the transversal unity its lateral roles presuppose. Wiggins’s criteria of individuation yield the same point: what individuates the continuant is a transversal relation to a sortal concept, not a relation among its parts.
When we find the frog’s transversal constitution of its Umwelt, we seem to treat it laterally as a structure described from outside in natural-historical judgments. If that were all we needed, the frog’s organs and behaviors would be, for us, just more intricate lateral facts. What blocks this, in my view, is that we can only disclose the frog’s affordance-field (Umwelt) as a governed field, rather than as a physical aggregate exhibiting a pattern, only because we are ourselves loci of transversal constitution and recognize the structure as such. The natural-historical judgment is laterally expressed but transversally grounded, and its very availability depends on the judger’s being a form of life whose own Welt is transversally constituted. (I am making use of the Welt/Umwelt distinction of Heidegger and Gadamer). This, incidentally, is why I think Thompson’s “enthymeme” was never really a missing premise. The aptness of natural-historical judgements is secured by the kinship of constitutive structure between discloser and disclosed.
This may be a long way back to the thread’s main topic. If the frog sits in our ontology in the way I suggest (as a transversal unity governing a lateral field, differing from us only in that it cannot express it self-consciously nor subject it to rational scrutiny) then natural goodness is not a queer normative extra laid over a value-free substrate. It is what the transversal governance of a life-form looks like when the field it governs is the self-maintaining pattern of the living thing, and what it becomes, at the reflexive tier, where (mere) flourishing becomes eudemonia. It is the answerability of a practical form of life to its own good. That’s the bridge from Thompson’s categoricals to Foot’s evaluations.