Naturalism is perhaps the most pervasive “-ism” in contemporary philosophy. Different variations of naturalism can be found in virtually all corners of theoretical and practical philosophy. Critics have rightfully noted that it is (a) often not clear what “naturalism” means exactly and, subsequently, (b) whether those who consider themselves naturalists in the same philosophical debate actually hold compatible, let alone the same, beliefs.

Among the different forms of naturalism that hold currency today, scientific naturalism seems to be the most widespread and therefore articulated. It can be summarized as the ontological thesis that what exists are solely the entities posited by the natural sciences and the methodological thesis that philosophical inquiry should take the results of the natural sciences as authoritative. The paradigm of scientific naturalism has received a growing amount of critical attention from within and outside of analytic philosophy in the last few decades. The main thrust of a host of these critiques is to “soften” the claim of scientific naturalism by rejecting its reductionist or even eliminativist implications, yet retaining a commitment to naturalism under a new description. This has led to a proliferation of new forms of naturalism that seek to broaden the criteria which determine what belongs to the natural world, usually self-titled as a “liberal” or “relaxed” naturalism. Within the analytic tradition, naturalism has been thus critiqued since the 1990s by thinkers like Hornsby, Strawson, Nagel, Stroud, Putnam, McDowell or more recently Baker, De Caro, Macarthur, Beale & Kidd, Cahill & Raleigh. Such critiques are commonly motivated by Neo-Aristotelian and/or Wittgensteinian intuitions. From outside the analytic tradition, phenomenologists in the Husserlian tradition as well as thinkers in the Idealist tradition have been steadfastly critical of scientific naturalism as well, albeit for different reasons. However, these new proposals all have to contend with scientific naturalism and its more restrictive criteria for what counts as natural (although these are debated in their own right).

The purpose of this special issue is to contribute to the ongoing critical discourse on naturalism at this critical junction where liberal naturalism must meet the demands of scientific naturalism in order to part ways with it. Accordingly, the issue’s sub-title “Challenges and New Perspectives” intends to name two sides of the same coin: new perspectives for a liberal or relaxed naturalism are bound up with the challenges posed to, and by, scientific naturalism. The contributions to this special issue reflect this two-sided approach, intertwining specific challenges to naturalism with new prospects and perspectives.

While the contributions cover a multitude of different issues regarding naturalism, we want to briefly shine a light on a selection of these to provide the reader with an overview. Two main challenges to scientific and/or liberal naturalism serve as a guiding thread that interconnects the contributions to this issue.

First, the ‘Placement Problem’: given that scientific naturalism restricts the scope of what entities belong to the realm of nature, certain phenomena do not seem to have a ‘place’ within this realm. Perhaps the most famous candidates for the Placement Problem are consciousness, normativity, value, and God. When confronted by an instance of the Placement Problem, the ontological and methodological commitments of scientific naturalism either call for a reduction or even elimination of the problematic phenomenon. The distortions of such reductionist analyses and the extreme regimentation of normal everyday discourse by eliminativist proposals are a prime motivator for a more liberal naturalism. The challenge for a liberal naturalism is to justify that a certain phenomenon does belong to the realm of nature without making the label “natural” and its connection to the sciences seem arbitrary.

Second, the ‘Reconciliation Problem’: it is perhaps liberal naturalism’s flipside of the same coin. According to the Reconciliation Problem, the liberal naturalist has to provide an account of how the ordinary and the scientific view of the world properly mesh. This problem is often formulated using Sellars’ distinction between the “manifest image” and the “scientific image” of the world that a philosophy informed by the natural sciences has to reconcile. Scientific naturalism does not face this issue because it affords the scientific view of the world clear ontological priority. But aiming to ‘balance’ the ordinary and scientific views raises the question how this balance is to be struck. This also pertains to the question how ‘liberal’ liberal naturalism ought to be and whether it can introduce a criterion for what is correctly called “natural” in the first place.

Mario De Caro’s contribution gives an overview of the problems just outlined and tries to define the parameters for a liberal naturalist response. The main thrust of De Caro’s article is to mount a defence of liberal naturalism by aiming to dispel the Reconciliation Problem. De Caro sketches three different ways liberal naturalists can respond to the Reconciliation Problem: heterogeneity, emergentism, and global supervenience. For each of these approaches, De Caro raises some possible grievances the scientific naturalist will have. Hence, this contribution does not provide a definitive answer yet, but opens up new avenues for further research into the ongoing discourse between scientific and liberal naturalists.

Contributions that centrally deal with the Placement Problem in a heads-on way are those by Price, Knowles, and Ellis. In previous works, Price has presented a ground-breaking argument for escaping the impasse of the Placement Problem without sacrificing the naturalist programme. This third way Price labels “subject naturalism”. In his contribution to the special issue, Price further specifies and defends his version of an expressivist analysis of discourse which underlies his subject naturalist approach. Knowles’ contribution takes stock of the critical debate in reaction to Price’s proposal and opens up a new avenue for alternative approaches that share its anti-representationalist paradigm but part ways with the subject naturalist project. Ellis’ contribution focuses on another outer limit of the Placement Problem, naturalism’s inherent contrast to supernaturalism, in order to show how even this limit may be pushed further without sacrificing a naturalist outlook and methodology.

Huw Price’s contribution discusses the underlying metasemantic theory of his subject naturalism, global expressivism, and contrasts it with Gibbard’s version of expressivism. Both expressivist approaches are quasi-realist: they explain how certain elements of discourse appear to be representational while actually serving an expressive function. The controversy concerns whether quasi-realism should be fully generalized, i.e. ‘global’, or remain ‘local’ to limited areas of discourse. Price focuses this question on Gibbard’s contention that naturalistic discourse retains a substantive notion of denoting which is identical to the word-world relation of tracking. Price argues against such an identification and for a more thoroughgoing quasi-realist analysis of discourse which, in a Sellarsian spirit, strictly separates the function of semantic word-word relations from the ‘picturing’ relation of tracking.

Jonathan Knowles’ contribution takes up Price’s project of global expressivism which aims to undercut the Placement of Problem of locating notions of the manifest image within a scientific image of the world through a semantic deflation of reference and other representationalist concepts. According to Price, this problem is only faced by an “object naturalism”, which is inextricably tied to representationalism, while it is avoided by “subject naturalism” that analyzes our discourse in a non-representational, quasi-realist fashion. Knowles aims to level the score in the debate by reassessing the objection against Price that representationalism and object naturalism are separable. Knowles argues in detail that this objection – which was raised, among others, by himself – fails to do justice to the dialectical situation. Price’s global expressivism retains the upper hand if it provides a coherent alternative to object naturalism that does not come with the potential costs of eliminativist or reductionist consequences. This puts the question whether global expressivism is coherent to the fore. In his discussion, Knowles sketches an enactivist alternative to global expressivism. Thus, his contribution shows that the semantic approach of anti-representationalism is still a viable alternative to object naturalism and that it holds multiple options for further exploration.

Fiona Ellis’ contribution continues the quest started by Rudder Baker for a formulation of naturalism that toes the line between scientific naturalism, supernaturalism, and liberal naturalism. Her target is to formulate a position that excludes reference to supernatural elements like witchcraft, ectoplasm or reference to a Platonic notion of God as extra-worldly. This leaves a notion of naturalism that excludes the transcendent, but expands what is considered to be immanent, i.e. natural, by including a conception of God as part of the world. This is the position of naturalistic theism.

Concerned with the intersection of the Placement and Reconciliation Problems are the contributions by Rouse, Elpidorou & Dove, and Spiegel. The former outline ways that the seeming constraints of the scientific naturalist framework may be extended from the inside, whereas Spiegel takes a more critical stance towards this approach. Rouse shows that a radical metaphilosophical conception of naturalism as a research programme can dissolve the widely assumed exclusion of the normative from the scientific image of the world, as it at least includes the normativity of scientific practice itself. Elpidorou & Dove pursue a similar metaphilosophical understanding of naturalism as a research programme on their own terms. Using this approach, they show that adaptation of the “free energy principle” enables physicalism to accommodate mental phenomena that are often seen as excluded from the scientific image of the world. Over against these metaphilosophical affirmations of naturalism as a research programme, Spiegel acts as a balancing critical voice that calls this assumption into question by presenting it with a dilemma.

Joseph Rouse’s article presents a critique of the metaphilosophical and metaphysical forms of scientific and liberal naturalism more commonly debated, by introducing points from the debate on naturalism in the philosophy of science. One mistake of scientific naturalism, according to Rouse, is to assume that deference to the methods of (natural) science is a surefire way to construe one’s ontological commitments. Instead, naturalism about science consists in acknowledging that there “is no better science than the science we have as an ongoing, historically developing research enterprise.” This implies that, contrary to what many philosophers believe, the scientific conception of the world is not non-normative. There is no single unified scientific picture of the world, and the variety of methods used in scientific inquiry are just tools, not guiding criteria for constructing ontology. In essence, Rouse urges (scientific and liberal) naturalists to drop an idealized or romanticized view of the natural sciences and take a closer look at what they actually do. The radicality in Rouse’s radical naturalism consists in it beginning at home, in “a naturalistic account of scientific practices and scientific understanding.”

The contribution by Andreas Elpidorou and Guy Dove aims to further work on their own physicalist project conceived of as a research program committed to finding compositional explanations for things that are only derivatively physical. The free energy principle approach in cognitive science and philosophy of mind asserts that all biological self-organizing systems must minimize variational free energy, a measure of the difference between the system’s internal states and the external states it perceives. This article seeks to integrate the free energy principle into physicalism as a research program.

Thomas J. Spiegel’s contribution critiques the by-now popular idea of reconceiving physicalism as an attitude or research program rather than a thesis, which is held by naturalists like Alyssa Ney or Michael Rea (cf. also Elpidorou’s and Dove’s contribution). This movement to reconceive naturalism as an attitude or program is due to pressure from Hempel’s dilemma and the coherence dilemma rendering naturalism untenable. Spiegel argues that opting for naturalism as an attitude (rather than a thesis) faces a third dilemma. On the one hand, naturalism as a non-truth evaluable attitude can simply be reformulated as a truth-evaluable statement, thereby leaving it exposed again to Hempel’s dilemma and the coherence dilemma. On the other hand, even if naturalism were to remain an attitude, it would render itself outside of the realm of rational justification which it nevertheless does require. Thus, reconceiving naturalism as an attitude is much less promising than ordinarily assumed.

Contributions that centrally deal with the Reconciliation Problem are those by Hutto, Gambarotto & Nahas, and Sachs. Hutto’s contribution addresses the core challenge to liberal naturalism that its solution to the Reconciliation Problem is “too liberal”, that is, that the realm of the natural is extended too far beyond the purview of the scientific image of the world. While Hutto formulates a general criterion to regiment inclusion into the realm of nature, the latter contributions aim to “fuse” the manifest and scientific images through a specific paradigm, the phenomenon of life. Gambarotto & Nahas propose a “post-Kantian naturalism” which shows how our manifest image of rational agency can be seen as continuous with organic life as part of the realm of nature. Sachs also draws on the phenomenon of life in a way that aligns with the post-Kantian project, however, he draws on the modern “organizational approach” in biology to overcome the dichotomy between the manifest goal-directedness of organisms and the strictures of the scientific image.

Daniel Hutto’s contribution further develops his preferred variation of naturalism introduced in recent years: relaxed naturalism. Relaxed naturalism “seeks to show how philosophy and the sciences can connect productively and have coop­erative dealings.” In doing so, it is not only opposed to scientific naturalism, but also to liberal naturalism as ontologically “too liberal”. It is too liberal because not every element of the manifest image deserves to be crowned with the property “natural”. Where liberal naturalists seem to be content with negative criteria for what is natural, Hutto tries to find a positive criterion. This positive criterion, he suggests, may lie in what Moyal-Sharrock calls ‘Wittgenstein’s Razor’, a methodological tool that cuts away at any kind of philosophical commitment that is picture-driven.

The contribution by Andrea Gambarotto and Auguste Nahas seeks to develop a third way between scientific and liberal naturalism regarding the question of what place agency occupies within nature. They formulate this third way in terms of the Reconciliation Problem between the manifest image and the scientific image: how to reconcile the autonomy and rationality of human agency with its placement in a deterministic universe? Their strategy is two-pronged: show that the manifest image of agency admits of degrees and show that the scientific image is open to include purpose-driven organisms as agents. Together this paves the way for a “bottom-up transformative approach to life-mind continuity”: while there is a qualitative distinction between biological agency and mindedness, it is not a dualism of ontological realms. To develop their approach, Gambarotto and Nahas combine insights from the tradition of post-Kantian naturalism in Schelling and Hegel with the modern ecological approach to organismal agency as autopoiesis. Their sketch of a Post-Kantian Naturalism shows that a robust notion of agency can be reconciled with the scientific image.

Carl Sachs’ contribution departs from Hans Jonas’ critique of cybernetics to re-frame the debate on naturalizing teleology. According to Sachs, Jonas makes two arguments. First, teleological concepts like need and interest and the “needful freedom” that organisms have in their pursuit are not reducible to the circular causality of cybernetic feedback loops. Second, phenomenology and the first-person perspective of living beings are the methodological basis for understanding life. Sachs takes up Jonas’ challenge. Regarding the first argument, he draws on the “organizational approach to naturalizing teleology” which presents a different model of circular causation in terms of a system’s organizational closure and thermodynamic openness. Regarding Jonas’ second argument, Sachs recommends that a distinction be made between a ‘Jonasian turn’ in enactivism as a philosophy of nature, which may be possible, and in enactivism as a research programme in cognitive science, which requires a different methodological basis.

In summary, the contributions to this issue meet the challenges of the Placement and Reconciliation Problems with new perspectives either on how to pursue the liberal naturalist project or to reconceive of scientific naturalism as a research programme. As Editors, we are happy to present the readers of Topoi with a diverse range of perspectives from younger as well as seasoned scholars. Given the spectrum of positions articulated here, the issue can justifiably be regarded as a representative cross-section of the current state of the art. We hope that the special issue will help clarify and stimulate the ongoing debate on naturalism and its challenges.