The emergence of a shared action ontology: Building blocks for a theory

Abstract

To have an ontology is to interpret a world. In this paper we argue that the brain, viewed as a representational system aimed at interpreting our world, possesses an ontology too. It creates primitives and makes existence assumptions. It decomposes target space in a way that exhibits a certain invariance, which in turn is functionally significant. We will investigate which are the functional regularities guiding this decomposition process, by answering to the following questions: What are the explicit and implicit assumptions about the structure of reality, which at the same time shape the causal profile of the brain’s motor output and its representational deep structure, in particular of the conscious mind arising from it (its “phenomenal output”)? How do they constrain high-level phenomena like conscious experience, the emergence of a first-person perspective, or social cognition? By reviewing a series of neuroscientific results and integrating them with a wider philosophical perspective, we will emphasize the contribution the motor system makes to this process. As it will be shown, the motor system constructs goals, actions, and intending selves as basic constituents of the world it interprets. It does so by assigning a single, unified causal role to them. Empirical evidence demonstrates that the brain models movements and action goals in terms of multimodal representations of organism-object-relations. Under a representationalist analysis, this process can be conceived of as an internal, dynamic representation of the intentionality-relation itself. We will show how such a complex form of representational content, once it is in place, can later function as a functional building block for social cognition and for a more complex, consciously experienced representation of the first-person perspective as well.

Introduction

Actions in the external world can be experienced as such, recognized, and understood. Simultaneously, the intentional content correlated with them (i.e., their satisfaction conditions resp. their intended goal-state) is interpreted by the observer as playing a causal role in determining the behavior of the observed other individuals. From a first-person perspective, the dynamic social environment appears as populated by volitional agents capable to entertain, similarly to the observer, an intentional relation to the world. We experience other agents as directed at certain target states or objects. We are “intentionality-detectors”: As human beings, we cannot only mentally build an “objective,” third-person account of the behaviors constituting the events of our social world. Beyond phenomenally experiencing the objective nature of a witnessed action, we can also experience its goal-directedness or intentional character, similarly to when we experience ourselves as the willful conscious agents of an ongoing behavior.

In the present paper we will provide and integrate some empirical and conceptual building blocks for a theory of the emergence of a common ontology between members of a group. We will examine, from a third-person scientific perspective, the fundamentally relational character of actions in the world. In particular, we want to look at the “ontological commitments” the brain makes when representing actions and goals. It will be further shown that the brain builds an ontology, an internal model of reality, which—on a very fundamental level within its representational architecture—incorporates the relational character of inter-actions between organism and environment, and that this architecture can actually be traced at the microfunctional level implemented in the brain’s neural networks. The same subpersonal ontology then guides organisms when they are epistemic agents in a social world: Interpersonal relations become meaningful in virtue of a shared action ontology.

An action ontology can only be shared and successfully used by two systems, if there is a sufficient degree of functional overlap between them, if they decompose target space in similar ways. We will posit that the cognitive development of social competence capitalizes upon such a shared ontology to trigger the timely onset of behaviors such as gaze following, shared attention, and mind reading, which will eventually give rise to a full-blown capacity to entertain mental accounts of the behavior and goal states of other agents. We will also propose that what makes humans special is the fact that their functional ontology is much richer in socially individuated goal representations and that their model of reality is not only rich and flexible, but that they can actively expand their own functional ontology by mentally ascribing distal goals to conspecifics.

Neuroscientific results discussing the functional properties of mirror neurons, a class of premotor neurons in the monkey brain, will be introduced. It will be proposed that mirror neurons can be conceived of as the dawning of what the equivalent matching systems in our human brains are the fully developed realization of: a fundamental and mostly unconscious representational structure capable to build a shared action ontology. However, in closing we will also provide an example for a late and high-level utilization of this structure: enabling beings like ourselves to mutually acknowledge each other as persons, and to consciously experience this very fact at the same time.