Theory & Psychology

This introduction provides a brief sketch of explanatory pluralism and related issues. It is argued that traditional ideas in the philosophy of science about connections between levels of explanation, autonomy and reduction are too simple to account for the multifaceted explanatory relations between psychology and its neighboring disciplines. Explanatory pluralism holds that theories at different levels can co-evolve and mutually influence each other, without reduction of the higher-level theory to the lower-level one. Establishing bridges between cognitive psychological and neuro-physiological theories may suggest problems and solutions, and thus foster further development, both ways. The ideas put forward in this Symposium provide resources for a pluralistic view on psychological explanation, and militate against the `single-plot story' that physiological reductionism holds up as an ideal to psychology.

Explanatory pluralism holds that the sorts of comprehensive theoretical and ontological economies that microreductionists and New Wave reductionists envision and antireductionists fear offer misleading views of both scientific practice and scientific progress. Both advocates and foes of employing reductionist strategies at the interface of psychology and neuroscience have overplayed the alleged economies that interlevel connections (including identities) justify while overlooking their fundamental role in promoting scientific research. A brief review of research on visual processing provides support for the explanatory pluralist's general model of cross-scientific relations and discloses the valuable heuristic role hypothetical identities play in cross-scientific research. That model also supplies grounds for hesitation about the correlation objection to the psychophysical identity theory and complaints about an explanatory gap in physicalist accounts of consciousness. These takes on psycho-neural connections miss both the sorts of considerations that motivate hypothetical identities in science and their fundamental contribution to progressive research. Thus, their focus on the contributions of research at multiple levels of analysis does not bar explanatory pluralists from considering heuristic identity theory (HIT). Arguably, it encourages it.

Contemporary reductionism nowadays comes in various strengths and flavors, ranging from restricted claims concerning the token identity of physical and mental events up to the more orthodox claims about the reducibility of psychological laws. This paper first provides a taxonomy of different versions of reductionism arranged in order of decreasing strength. Against this backdrop it is argued that classical arguments in favor of an absolute autonomy of psychology and of the special sciences fall far short of their intended conclusion. Instead the paper develops what it takes to be more promising arguments based on the notion of multiple supervenience that underwrite the notion of explanatory pluralism and make room for a systems account of higher-order processes sanctioning downward causation without violating the laws of micro-physics.

Physicalism claims that the ontology of the world coincides with the ontology of physics. My paper offers a discussion and assessment of this claim. First, I explain why physicalism implies a straightforward ontological reductionism; hence, on an ontological reading, `non-reductive physicalism' is a contradiction in terms. Second, I argue that, without further specification, the content of `the ontology of physics' is completely undefined. Since this content is usually taken for granted in the philosophy of psychology and the philosophy of mind, the notion of physicalism has no positively determinable meaning. Third, by taking into account the full particulars of how observations of physical phenomena are realized in practice, I question the claim that reductive physicalism is confirmed by the cognitive achievements of connectionist networks.

The main question of this contribution is how to define a (relatively) autonomous psychological level. It will be introduced by some remarks on the general problem of reduction and explanatory levels. The arguments for a psychological level will be applied to the question: in what sense can (mental) causation figure in psychological explanations? As it turns out, much depends on what, precisely, we want to know: are we interested in psychological questions about events at the neurological, physiological level; or in psychological questions about meaningful actions in intersubjective contexts?

In this paper, two recent interpretations of current work in behavioral genetics are rejected. Genetic reductionism, the view according to which genetic properties are causally sufficient for phenotypic traits, is dismissed because it ignores the fact that there are not only causal pathways from DNA to phenotype but also pathways that feed back from, for instance, the cytoplasm or the outside world to the genetic material. The complexity of development is acknowledged in the view known as developmentalism, which claims that a complex causal network of genetic and non-genetic factors is responsible for phenotypic outcomes. However, genetic explanations, at least in some contexts, do seem to have a privileged status. Heuristic identity theory appears to offer a more adequate interpretation for behavioral genetics. It is in many cases very illuminating to hypothetically identify phenotypic traits with genetic properties. We claim that McCauley and Bechtel's proposal calls for at least two constraints to avoid a wild proliferation of implausible identities. First, more emphasis should be placed on explanatory failures. Second, the most interesting identifications are those that make `qualitative leaps', that is, they must apply across distinct levels of analysis.

What is the theological significance of the philosophy of mind and debates on reductionism? Religious experience is rooted in processes in the brain (e.g. d'Aquili). Understanding this may offer the theologian some arguments against dismissive accounts of religion, but it challenges claims regarding a non-natural referent. Problems with treating the world-God relationship as analogous to the one between brain and mind (as Philip Clayton does) are pointed out. The idea that Christians must side with irreducibilists in the philosophy of mind is criticized. Ontological irreducibility seems theologically unnecessary, as God can be the creator of a world with one, two or any other number of aspects. Epistemological irreducibility is insufficient for such a theology, as it comes with a naturalistic understanding of human nature. Thus, contemporary philosophy of mind may be an ally in arguing against an easy dismissal of religious practices and convictions, but at the same time it challenges a supernaturalist view of religion.

Numerous studies have yielded data consistent with the hypothesis that the `Big Five' personality traits are highly stable in adulthood. For McCrae and Costa, such findings suggest a need to significantly revise our understanding of adult personality development: stability, rather than change, appears to be the rule. The central purpose of the present essay is to demonstrate that McCrae and Costa's strong claims in favor of personality stability are not contingent upon any set of empirical observations. Rather, they necessarily follow from the acceptance of two related pre-empirical assumptions: (a) personality traits are transcontextual; and (b) revelations of the `true' personality structure must be reliable. If these propositions are accepted without qualification, then evidence inconsistent with the stability thesis can simply be attributed to the `inadequate' conceptualization or measurement of traits. Thus, McCrae and Costa's arguments in favor of personality stability are insensitive to falsification. Implications for researchers interested in the study of life-span personality development are discussed.

The strong claim that the stability of personality is not falsifiable is wrong because it has been falsified under some conditions. The weaker claim that it is trivial because traits are defined as transcontextual consistencies does not hold because the transcontextual nature of traits has no implications for long-term stability. Traits are important both because of their pervasive influence on thoughts, feelings and actions, and because of their centrality in many people's identity. Nevertheless, there is more to personality than traits, and many other psychological phenomena also merit study by personality psychologists.

McCrae seems to believe that the empirical status of the stability thesis is guaranteed by virtue of the fact that scores on measures of personality traits are always free to change over time. Yet, my thesis that trait stability is a noncontingent truth is not predicated on specific claims regarding phenotypic manifestations of personality traits. Rather, I maintain that McCrae and Costa's pre-empirical assumptions logically require an interpretation of the human personality in terms of stable traits. In this rejoinder, I further clarify this `strong' claim and I defend my `weaker' claim that the transcontextual nature of traits loads the dice in favor of empirical demonstrations of long-term stability.