Diagrams as the Centerpiece of an Enactivist Epistemology

As has been recently stated by many (Caruana, Testa, 2021; Gallagher, 2017, Menary, 2007), Pragmatism is a philosophical precedent and an ally of enactivism. The present work, whose title explicitly recalls that of Frederik Stjernfelt (2000), aims at providing a contribution to this scenario, showing how the notion of diagram, central to the epistemology and semiotics of the father of pragmatism, Charles Peirce, can coherently integrate and enhance the enactivist epistemology. 

Enactivism proposes a theory of the interactive mind (Gallagher, Froese, 2012; Di Paolo, De Jaegher, 2012) based on basic actions and the direct perception of external affordances, which is opposed to both Theory Theory (TT) and Simulation Theory (ST). Both of the latter base their explanations of social cognition (perceiving the intentionality of the actions of others) on representations within the brain. 

Two problems of the enactivist theory are highlighted: a) the problem of the actual mental-constitutive role played by basic actions (Satne, 2020); b) the problem of holistic explanations that must each time refer to the entire brain-body-environment system (Gallagher, 2017; Hutto, Myin, 2013). 

Even if the semiotic stance on mental representations is not of a piece, I will argue that Peirce's semiotics, and his theory of diagrams in particular:

1.  is consistent with the enactivist vocabulary (to Peirce, a diagram is a sign which, just like the affordances recalled by enactivists, is co-constructed by the relation of a subject with its environment; see Gibson, 1979; to Chemero, 2003; 2009, in particular, affordances are relations; on the semiotic side, see Violi, 2007; Paolucci, 2019);
2.  helps to solve a semiotic confusion that characterizes most of contemporary cognitive theories, namely that between signs and representations (Deely, 2009). To recognize this distinction means to take the way of signs (opposed to that of concepts or of representations) in cognitive science. Moreover, semiotics offers to the enactivists a theory of propositions that solves problem (a) mentioned above without the appeal to mental representations (see Hutto, 2011, a call for a teleosemiotics as opposed to representationalist teleosemantics).
3.  allows the integration, within a unified enactivist theory of mind, of TT and ST as its aspects reformulated in terms of habits and external affordances, corresponding to the general and the iconic part of the diagram structure, respectively (see Stjernfelt, 2007; Tylén, et al, 2014);
4.  by placing the pragmatist notion of habit at the center, it allows the identification of a level of relevance for enactivist explanations that frees them from the problem (b) of holism (cf. Noë, 2012).