I received a B.A. in pedagogy and art history from the University of Karlsruhe (TH), a M.A. in philosophy from the University of Constance and a PhD in philosophy from the University of Geneva. I worked as a postdoc at the University of Geneva and the Università della Svizzera italiana (USI). I also taught at the Universities of Bern, Geneva and Neuchâtel and I co-organized the weekly research seminar of eidos from 2017 to 2021. Since November 2022, I'm working at LanCog at the University of Lisbon as a FCT assistant researcher.
My research has been mainly in metaphysics, partly boardering on the philosophy of science (main topics: essence, modality, laws of nature, metaphysical indeterminacy), and in the philosophy of language (vagueness, two-dimensional semantics). I also have interests in the history of philosophy (early analytic philosophy, early realist phenomenology), aesthetics (especially of music), epistemology (a priori/a posteriori distinction, epistemology of modality and essence, understanding), philosophy of mind (dualism/materialism, panpsychism) and recently also in value theory (value pluralism). I am happy to engage with relevant research in other areas of philosophy and other disciplines, such as linguistics or the natural sciences. I'm also a fan of collaborative teaching and research (Linnemann number 1).
I'm currently pursuing a longer individual research project on indeterminacy: Understanding the Nature of Indeterminacy (LanCog, Centre of Philosophy, University of Lisbon).
I've previously been involved in two SNSF-funded research projects in Switzerland as a postdoc, having contributed substantially to the project proposals: Identity in Cognitive Science, Quantum Mechanics, and Metaphysics (USI, 2019-2021) and Indeterminacy and Formal Concepts (University of Geneva, 2014-2017).
So far, I've taught courses and seminars in metaphysics, philosophy of language, logic, history of analytic philosophy, and also some subjects in epistemology and the philosophy of science, some at undergraduate, some at graduate level, some in German, some in English, some in French, some in Germany, most in Switzerland.
For (even) more details, please see my academic cv.
My e-mail address: mail (a) robert-michels.de. Comments or feedback on papers always welcome!
Project: Indeterminacy in Science
Since February 2025 lead a FCT-funded exploratory project on indeterminacy in science, which brings together researchers from Portugal, Italy, and Switzerland. The project investigates whether science leaves room for or even gives rise to indeterminacy. For more information, please visit the
Indeterminacy in Science project website.
Papers and dissertation (click titles for abstracts)
Motto:
Während ich einen kurzen Text, den ich einige Tage zuvor geschrieben hatte, dessen ich mir aber nicht wirklich sicher war, zu korrigieren oder noch zu ergänzen versuchte, fiel mir ein längeres Haar vom Kopf auf das Papier. Es lag da, nur wenig gekrümmt, schräg von links unten nach rechts oben über das Blatt hin.
Erich Fried
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Humansplaining: Is it a thing? Is it bad? — co-authored with Sanna Hirvonen (forthcoming in AI & Society's Curmudgeon Corner)
In this note, we discuss the possibility of humansplaining, where humansplaining is, in analogy to mansplaining, a human's act of unnecessarily and unjustly explaining something to an AI which is an expert on that topic. We argue that, assuming a suitably developed AI which is capable of being explained to in the first place, humansplaining would be bad for similar reasons as mansplaining and that the risk one runs of engaging in it would vary depending on the explained topic and in particular on whether the natures of the explainer, the explainee, or both allow them to have expertise in that area.
Links: published version (free to read online),preprint on philpapers, local copy.
In 1924, the Munich-school phenomenologist Moritz Geiger argued that there are dynamic essences. His two examples are the tragic, and being human, his main ideas are that what it takes to be tragic varies over time historically and that what makes an organism human varies across different stages of its ontogenetic development. He hence points to two ways in which essences may be dynamic, that is, subject to change. The current paper takes Geiger’s view seriously and assumes that it poses an explanatory challenge for the, then and now, standard view that essences are 'Platonic', i.e. cannot be subject to change. In the first part of the paper, I introduce Geiger's view and a bit of its historical context, in the second, I formulate the challenge it poses to the standard 'Platonic' view of essence. In the second part, I first discuss how this challenge can be met by a contemporary view of essence discussing three potential responses. The first relies on a notion of relativized essence, the second on the distinction between determinables and determinates, the third and last one on multidimensional properties. Finally, I argue that the last of these three proposals may be preferable to the other two.
Links: preprint on philpapers, local copy.
According to the standard Humean theory of the laws of nature, Lewis' Best System Analysis (BSA), laws of nature have their status at least partly as the result of an optimal trade-off between scientific values such as simplicity and descriptive strength. This idea has recently come under pressure. Authors like Roberts and Woodward have pointed out that there might, pace what proponents of the BSAs like to suggest, be no such trade-off in the way laws of nature are identified in the natural sciences. Roberts has it that considerations of strength in theory choice are never compromised by simplicity considerations; and Woodward argues that choices between scientific theories and the associated laws often rather involve a threshold of descriptive strength which has to be met before simplicity can even begin to matter.
In this paper, we make three points: first, we employ recent results from automated scientific discovery (or rather a subfield of it known as `symbolic regression') to provide concrete support for Roberts and Woodward's point that scientific theories are chosen based on strength-thresholds. Second, drawing on the same example, we argue that discussions of the BSA involve an overly simplistic view of what a trade-off between theoretical virtues amounts to; taking into account how trade-offs are treated in scientific practice, the idea of there being a single optimal theory has to make way for the view that a properly operationalized trade-off allows for a whole Pareto front of equally optimal theories. Third, we argue that a threshold behaviour with respect to a virtue like strength is not only compatible with this more systematic yet more complex view of trade-offs but also helps to bring it in line with the BSA's original preference for a single, or given the possibility of multiple optimal theories, a small number of best systems.
Links: preprint on philsci-archive, preprint on philpapers, local copy.
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Graded Qualities — co-authored with Claudio Calosi (Synthese 205:116 (2025))
The idea that qualities can be had partly or to an intermediate degree is controversial among contemporary metaphysicians, but also has a considerable pedigree among philosophers and scientists. In this paper, we first aim to show that metaphysical sense can be made of this idea by proposing a partial taxonomy of metaphysical accounts of graded qualities, focusing on three particular approaches: one which explicates having a quality to a degree in terms of having a property with an in-built degree, another based on the idea that instantiation admits of degrees, and a third which derives the degree to which a quality is had from the aspects of multi-dimensional properties. Our second aim is to demonstrate that the choice between these account can make a substantial metaphysical difference. To make this point, we rely on two case studies (involving quantum observables and values) in which we apply the accounts in order to model apparent cases of metaphysical gradedness.
Links: published version (open access), preprint on philpapers, local copy.
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History of Essence: Contemporary (Analytic Tradition) — (in: Koslicki, K. & Raven, M. J. (Eds.), The Routledge Handbook of Essence in Philosophy, Routledge, 2024)
This paper gives an overview of the history of the notion of essence in 20th century analytic philosophy. One the one hand, it traces a rather stringent development which leads from the anti-essentialism of early analytic philosophers like Carnap, Schlick, and Stebbing, through Quine's rehabilitation of metaphysics coupled with his skepticism about modality, via work on the semantics of modal logic and on the (modal) semantics of proper names by Barcan Marcus, Kripke and others from the 1960s-1980s and the introduction of the contemporary notion of metaphysical necessity (Kneale, Kripke) to Fine's neo-aristotelian primitivism about essence. On the other hand, it illustrates that the sui generis notion of metaphysical necessity which is closely tied to essence fills a theoretical gap which was already hinted at in Moore's work on intrinsicality and became evident in Wittgenstein's problematic attempt to address the colour incompatibility problem in the Tractatus.
Links: preprint on philpapers, local copy, publisher's website.
Two approaches to elevating certain laws of nature over others have come to prominence recently. On the one hand, according to the meta-laws approach, there are meta-laws, laws which relate to laws as those laws relate to particular facts. On the other hand, according to the modal, or non-absolutist, approach, some laws are necessary in a stricter sense than others. Both approaches play an important role in current research, questioning the ‘orthodoxy’ represented by the leading philosophical theories of natural laws—Humeanism, the DTA view, dispositional essentialism and primitivism. This paper clarifies the relations between these two emerging approaches, as well as their applicability to physical laws and the status of the challenges they pose for standard theories of laws of nature. We first argue that, despite some significant similarities between the two approaches (especially in the context of Lange’s counterfactual account of laws), they are in general distinct and largely independent of each other. Then, we argue that the support for meta-laws from physical theory and practice is more questionable than usually presented.
Links: published version (online first) (open access), Philsci archive preprint, local copy.
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Plural Metaphysical Supervaluationism — co-authored with Cristian Mariani, Giuliano Torrengo (Inquiry 67 (6), 2005–2042 (2024))
It has been argued that quantum mechanics forces us to accept the existence of metaphysical, mind-independent indeterminacy. In this paper we provide an interpretation of the indeterminacy involved in the quantum phenomena in terms of a view that we call Plural Metaphysical Supervaluationism. According to it, quantum indeterminacy is captured in terms of an irreducibly plural relation between the actual world and various misrepresentations of it.
Links: published version (subscription required), final draft version.
A common feature of all standard theories of the laws of nature is that they are "absolutist": They take laws to be either all metaphysically necessary or all contingent. Science, however, gives us reason to think that there are laws of both kinds, suggesting that standard theories should make way for "non-absolutist" alternatives: theories which accommodate laws of both modal statuses. In this paper, we set out three explanatory challenges for any candidate non-absolutist theory and discuss the prospects of the two extant candidates in light of these challenges. We then develop our own non-absolutist theory, the essentialist DTA account, which combines the nomic-necessitation or DTA account with an essentialist approach to metaphysical modality in order to meet the three explanatory challenges. Finally, we argue that the distinction between kinematical and dynamical laws found in physical theories supports both non-absolutism in general and our proposed essentialist DTA view in particular.
Links: published version (open access), PhilSci archive preprint, local copy.
In a recent paper, Tuomas Tahko has argued for a hybrid view of the laws of nature, according to which some physical laws are metaphysically necessary, while others are metaphysically contingent. In this paper, we show that his criterion for distinguishing between these two kinds of laws—which crucially relies on the essences of natural kinds—is on its own unsatisfactory. We then propose an alternative way of drawing the metaphysically necessary/contingent distinction for laws of physics based on the central kinematical/dynamical distinction used in physical theorising, and argue that the criterion can be used to amend Tahko's own account, but also that it can be combined with different metaphysical views aboutthe source of necessity.
Links: published version (open access), PhilSci archive preprint, local copy
Vaidya has recently argued that we can gain objectual understanding of essence through a version of Husserl's method of eidetic seeing adapted to the notion of essence discussed in contemporary metaphysics.
To make this point, he argues that Husserl's method cannot produce knowledge of essence, since it is subject to a vicious epistemic circularity.
In this paper, I argue against Vaidya that his application of Husserl's method in an epistemology of essence based on objectual understanding is subject to a similar vicious epistemic circularity.
While Vaidya's method can be modified to avoid this problem, I argue that an amended version of it fails to meet two plausible quality standards for method for acquiring objectual understanding of essence.
I also raise two further problems for it, which arise for any contemporary epistemology of essence which relies on Husserl's method:
Such theories per default rely on a rationalist view of essence which is widely rejected by contemporary philosophers and given the way Husserl's method works, they furthermore conflate the notions of de re necessity and essentiality.
The paper ends with a brief general discussion about the the use of Husserl's method in the epistemology of essence and about the idea that it should focus on understanding instead of knowledge.
Links: published version (open access), final draft version
This paper discusses a particular approach to the epistemology of modality which is based on the idea that we can know that a state of affairs is metaphysically possible, if it is correctly conceivable, where correct conceivability is conceivability informed by knowledge of essence.
The approach was discussed, but not endorsed, by Rosen in his paper "The Limits of Contingency" with which I also engage in my paper "The Limits of Non-Standard Contingency".
The starting point of the paper is an argument to the conclusion that the approach is equivalent to the essentialist theory of modality, a metaphysical theory which is not designed to address epistemic questions.
This argument naturally suggests the objection that correct conceivability is of no use in the epistemology of modality.
In response to this objection I argue that correct conceivability can still play a somewhat limited epistemological role as an epistemic ideal in a bifurcated theory in which regular conceivers can become competent conceivers with respect to a subject by partly grasping the relevant essences.
Links: published version (free to read online), final draft version
This is a paper about the Essentialist theory of modality, which I also discussed in my dissertation.
In it, I distinguish four different definitions of metaphysical necessity which derive from Kit Fine's influential proposal that this notion should be defined in terms of essence.
I explain why one of them has to be rejected and then argue that the remaining three definitions are extensionally equivalent, i.e. give us exactly the same metaphysical necessities.
I then argue that one of the three definitions, namely Fabrice Correia's, should be considered the standard definition, since the others face certain problems connected to the primitive Essentialist notion on which Fine's Essentialist framework is based.
Links: published version (free to read online), published version (subscription required), final draft version
In his paper "The Limits of Contingency", Gideon Rosen argues that the notion of metaphysical modality is systematically ambiguous.
His argument is striking for two reasons.
First, its main conclusion calls into question the many philosophical theories and claims which explicitly or implicitly rely on the standard notion of metaphysical modality.
Second, Rosen's main argument is crucially based on a sub-argument which has been used by Kristie Miller to argue for Metaphysical Contingentism, the controversial view that some claims of fundamental metaphysics are metaphysically contingent, rather than necessary.
In this paper, I explicate this crucial sub-argument argument based on Rosen's suggestive, but brief statement.
My first main point is that the most straight-forward explication of the argument fails to support Rosen's conclusion that the notion of metaphysical modality is systematically ambiguous.
I discuss two possible ways to save the argument and rebut them by arguing that they both entail a problematic view about the meaning of formal concepts, such as that of being an element of a set.
My second main point is that the argument can only be used to support a rather particular version of Metaphysical Contingentism.
Links: published version (free to read online), published version (subscription required), final draft version
The main idea which I motivate and defend in this paper is that propositions which express essential truths about certain objects have their truth grounded by facts which involve those objects. A truth-ground in this sense is a fact which makes it the case that the relevant proposition is true. (While I leave this open in the paper, I am sympathetic to the idea that truth-grounds are simply truth-makers.) I motivate the principle by providing two arguments for it, one based on the idea that the canonical notion used to capture claims about essence in the recent literature "is true in virtue of the nature of" is a special variety of truthmaking. I then defend the principle against three objections drawn from the recent literature on essence and grounding and then use the principle to argue that Fine's notion "... is true in virtue of the nature of ..." in its constitutive reading is non-monotonic. Finally, I respond to an argument due to Tahko, according to which truth-grounding is not genuine grounding. (There's quite a lot happening in this one!)
Links: published version (open access), local copy
In this paper, I defend David Lewis's modal realist theory of modality against a recent objection by John Divers.
Divers argues that the theory cannot account for the truth of modal comparative sentences like "The actual tallest thing could have been taller."
His argument is based on the two ideas that first, to be comparable regarding a spatiotemporal magnitude such as tallness, two objects have to be in the same possible world, which in Lewis's sense means they have to be in the same (analogical) spacetime, and that second, modal realists are forced to treat this sentence as involving a cross-world comparison of tallness between objects in distinct possible worlds.
I respond to Divers's argument by showing that modal realists can help themselves to a standard approach from semantics, according to which the objects compared in a comparative sentence are degrees (e.g. of tallness).
To make this point, I argue that this approach is compatible with Lewis's modal realism.
Links: published version (open access), final draft version
Two-dimensional semantics is a semantic theory which promisses a unified treatment of the important philosophical notions of a priority and metaphysical modality by associating the expressions of a language with two different kinds of meanings. In this paper, I defend a variant of this theory, strong two-dimensionalism, against a central argument from Scott Soames's 2005 book "Reference and Description: The Case Against Two-Dimensionalism". Soames argues that strong two-dimensionalism fails to deliver the intuitively correct truth-values for certain complex sentences involving the modal notion of necessity, a belief report and a claim that the reported belief is true. In response, I first develop a formal semantics for strong two-dimensionalism which allows for two distinct semantic clauses for claims about the truth of reported beliefs. I then show that Soames's claim is correct if the semantics includes one of the two clauses, but false if it includes the other. This means that defenders of strong two-dimensionalism have a way of resisting Soames's argument. Finally, I suggest some replies to an important objection against the version of strong two-dimensionalism which is immune to Soames's argument.
Links: published version (subscription required), erratum to the published version (subscription required), final draft version (the final draft version has more conveniently placed tables, doesn't require a subscription, and incorporates the two corrections listed in the erratum)
Essentialists claim that we can distinguish between an object's essential and its accidental properties. According to them, an object's essential properties are those without which it cannot be what it is. The number two is for example essentially such that it is even, but only accidentally such that it is my favourite number.
Following important developments in modal logic during the 1960s and 70s, the orthodox view was that the essential properties of an object are its necessary properties. In his influential 1994 paper "Essence and Modality", Kit Fine argues that the orthodox view is wrong. His two main claims are that first, essentiality cannot be defined in terms of necessity and second, that necessity should instead be defined in terms of essentiality.
In my dissertation, I aim to undermine both of his claims in order to defend a variation of the orthodox view. To do this, I first develop Fine's proposal for an essentialist definition of necessity into a more general essentialist theory. I then raise a series of problems for the resulting theory, one being that it provides no adequate treatment of iterated modalities. Finally, I introduce and defend a novel definition of essentiality in terms of metaphysical necessity and a notion of metaphysical dependence.
