An Apophaticism of the Human: Gregory of Nyssa & Neuroscientific Naturalism

Many of the contributors of the “After Science and Religion” project suggest that the methodological naturalism of contemporary scientific practice inevitably entails, at least a tacit, metaphysical naturalism (see Harrison 2021, 482; Tyson 2022, 165, 171, 174, 180; Hanby 2022, 141, 163; cf. Schindler 2022, 234). Ironically, these authors agree with Christian physicalists like Nancey Murphy (2008) who suggest that the successes of the physicalist sciences of the mind render the soul obsolete, i.e., that the fruitfulness of the methodologically naturalist approach to the human compels the adoption, even by Christians, of a metaphysically naturalist understanding of the human being. While the Christian physicalists celebrate this move from methodological physicalism to Christian physicalism and these members of the “After Science & Religion” project lament it, both agree that the move is valid and likely unavoidable. 

At other moments of the “After Science & Religion” project, however, its members suggest that naturalism can be a useful abstraction that may not imply any metaphysical commitments if “carefully regulated” (Tyson, 2022, 173; c.f. Harrison 2022, 173). I will follow this second group to develop a theological interpretation of the brain sciences that respects physicalist models without abandoning traditional Christian beliefs in a separable soul. This interpretation will draw on two sources. First, I recover Gregory of Nyssa’s exegesis of the image of God as the cause of our inability to understand ourselves. As images of the incomprehensible God, we share in His incomprehensibility. Gregory especially attaches this incomprehensibility to the mind (nous) and its relationship to the body (De hominis opificio 11.3/ PG 44: 156B). A theological anthropology inspired by Gregory will not expect to find one single model of the human being that explains all that humans do—from thinking, willing, and feeling to persisting with God after death (Wis 3:1; Rev 6:9-11). Such a theological anthropology will welcome multiple models of the human being even as it is free to reject many as unfitting. Indeed, if we look to the greatest source of Christian theological anthropology, Paul, we find him speaking of the human being through a variety of models that he never seeks to synthesize from soul- body models, to spirit-soul-body, to spirit-flesh, to both heart-centered & head-centered models. 

In recent work in the philosophy of science, we find a focus on the scientific practice of model-building (see especially Frigg 2023), a practice that is nearly ubiquitous in the brain sciences. Several philosophers in this field have focused on the similarly widespread practice of abstraction and idealization in model-building. What is relevant to our purposes is that idealization and abstraction are ways of misrepresenting systems, of leaving out or distorting aspects of the target system, that not only support representation but also are thought to underwrite the success of the many models. Representing a string’s mass as zero allows us to construct the model of the simple pendulum. The success of the simple pendulum model does not, however, underwrite the belief that the pendulum’s string has zero mass any more than Hardy Weinberg models suggest that populations are infinite. 

Gregory of Nyssa’s insistence on the incomprehensibility of the human being combined with Frigg’s description of models, allows a reinterpretation of the mind-brain identity thesis that underpins neuroscientific models. Theologians can understand the mind-brain identity thesis as an idealization, a distortion of human reality that nonetheless supports successful models in the brain sciences that can coexist with models in theological anthropology that posit a separable soul. Even if the mind-brain identity thesis were able to explain the human things (see Ritchie 2019) it would fail to explain the Christian things: the intermediate state (Wis 3:1; Rev 6:9-11), the promise of a resurrection that is not a mere recreation (1 Cor 15), and personal identity over time despite the changing matter & structures of the body, etc. Christian theologians have more to explain and are warranted in building more models to do so. 

With the help of a fourth century bishop and contemporary approaches in philosophy of science, we can affirm the methodological physicalism of the brain sciences without falling into a metaphysical commitment to physicalist views of the human being. A models approach to theological anthropology allows some of the worries of the Christian physicalists and of the members of the “After Science and Religion project” to be assuaged. On the one hand, the successes of neuroscience and the legitimacy of its methods are respected; on the other hand, theology can be bold enough to develop its own models and to retain its own traditional commitments. 

If we are truly to follow the lessons of Territories, we need to do more than replace pro-science essentialism with anti-science essentialism (see Reeves 2022). Instead, we need a more local approach (Reeves 2019) rooted in particular theological traditions,  as we find in the emerging science-engaged theology project (see Perry & Leidenhag 2021; Perry & Ritchie, 2018). This local approach, however, should not ignore methodological questions (see Davison 2022) nor engage with science uncritically. The approach that I try to model in this paper is a theology that engages science historically and philosophically: a historical and philosophical science-engaged theology (HPSET).