Massive Modularity: An Ontological Hypothesis or an Adaptationist Discovery Heuristic?

ABSTRACTCognitive modules are internal mental structures. Some theorists and empirical researchers hypothesise that the human mind is either partially or massively comprised of structures that are modular in nature. Is the massive modularity of mind hypothesis a cogent view about the ontological nature of human mind or is it, rather, an effective/ineffective adaptationist discovery heuristic for generating predictively successful hypotheses about both heretofore unknown psychological traits and unknown properties of already identified psychological traits? Considering the inadequacies of the case in favour of massive modularity as an ontological hypothesis, I suggest approaching and valuing massive modularity as an adaptationist discovery heuristic. AcknowledgementI am grateful to the editors and three anonymous reviewers who shared with me useful suggestions and constructive criticism. This paper is derived from my doctoral dissertation, which was defended at Lingnan University in 2021, as well as presentations I gave at the Science of Consciousness 2019 conference in Interlaken, Switzerland and at the EENPS 2021 conference in Belgrade, Serbia. Thanks to the University Grants Committee (UGC) of Hong Kong for its support over the past years.Disclosure StatementNo potential conflict of interest was reported by the author(s).Notes1 Recent research argues that visual perception, which is part of the peripheral systems of human mind, is top-down influenced and thus not informationally encapsulated. (For an exhaustive review of the literature, see Collins & Olson, Citation2014.) According to the data this research presents, visual perception is influenced by beliefs, desires, emotions, motivations, and so on (Siegel, Citation2012). If such is the case, then visual perception is cognitively penetrable and not modular. This recent research could be used as empirical evidence against the distinction between perception and cognition (Clark, Citation2013). In opposition to this view, Firestone and Scholl (Citation2016) contend that ‘there is in fact no evidence for such top-down effects of cognition on visual perception’ (p. 3).2 Neil Harbisson is an individual born with achromatopsia (a rare condition also known as ‘color blindness’), who claims to be the first ‘officially recognised’ cyborg of the world since the United Kingdom Passport Office accepted the inclusion of the electronic hardware attached to his head in his passport picture. Harbisson claims that the antenna is an organ, and not a device.3 There is not a univocal definition of modularity in biology (Wagner, Mezey & Calabretta, Citation2005). Yet this lack of analytical precision does not undermine the relevance of the concept of modularity for understanding biological phenomena. The concept of biological modularity is connected to properties such as dissociability (Needham, Citation1933) and quasi-independence (Lewontin, Citation1978). The reading of these properties—and hence the reading of biological modularity—is purely in terms of functional specialisation (Barrett, Citation2015b). This means that living complex organisms must be functionally dissociable into specialised traits that can be semi-independently modified by natural selection without affecting other specialised traits of the organism. In which case, ‘modularity allows the adaptation of different functions with little or no interference with other functions’ (Wagner, Citation1996, p. 38). Thus, the concept of modularity articulates a ‘building block hypothesis:’ new improvements do not compromise past achievements (Wagner & Altenberg, Citation1996). This is a key idea in evolutionary developmental biology or ‘evodevo.’ Modules are not innate in the sense of being ‘preformed.’ They are results of evolved developmental systems and gene-environment interactions. It is worth emphasising that the proximity between the notions of cognitive and biological modularity explains why there are some important attempts to understand cognitive modularity just as a special case of biological modularity. In this respect, according to Sperber (Citation2005), ‘if cognitive modules are real components of the cognitive system and not mere boxes in a nominalist flow-chart model, then they’re a subtype of biological modules’ (p. 55).4 That ‘human cognitive capacities are constrained by computational tractability’ is what van Rooij (Citation2008) calls ‘the tractable cognition thesis.’5 This idea can interpreted as a kind of instrumentalism (for more about this point, see the next footnote). It’s beyond the limited ambitions of this paper to discuss the arguments in favour and against instrumentalism in the philosophy of science. For more about instrumentalism, see Rowbottom (Citation2019).6 There has been an intense debate over adaptationism in the last four decades. Taking into account the distinction between empirical adaptationism, explanatory adaptationism, and methodological adaptationism proposed by Godfrey-Smith (Citation1999, Citation2001), the adaptationism referred to by means of the expression ‘adaptationist heuristic’ in this paper is neither empirical adaptationism—because it does not require to endorse the thesis that natural selection is the key to predict and explain most of the outcomes of evolutionary processes, as most mutations are not adaptive but neutral or nearly neutral—nor explanatory adaptationism—because it does not require to endorse the thesis that the problem of apparent design is the most important in biology. The adaptationism referred to by the expression ‘adaptationist heuristic’ is methodological adaptationism. This version of adaptationism recommends studying biological systems looking for features of adaptation and design. Here adaptationism is seen as a research strategy or working starting point. There are no underlying empirical claims about how the world is. There is not a philosophical valuation of the role of natural selection either. ‘There is nothing particularly new in this logic, which is also the basis of functional anatomy, and indeed of much physiology and molecular biology’ (Maynard Smith, Citation1978, p. 31). In the realm of psychology, the task is not trying to make sense of already known psychological traits in terms of ingenious—and sometimes outlandish—hypotheses that present them as adaptations (post hoc storytelling) but trying to discover either actual psychological adaptations that are heretofore unknown or unknown properties of already known psychological adaptations. Pace Gould (Citation1997a, Citation1997b), this appeal to adaptationism is not a matter of parochial and dogmatic fundamentalism. Adaptationism qua heuristic yields testable hypotheses about potential adaptations and the specific selection pressures (adaptive problems) that shaped them.