Thomas Metzinger

Cognitive enhancement aims at optimizing a specific class of information-processing functions: cognitive functions, physically realized by the human brain. This article deals with ethical issues in cognitive enhancement. It discusses some standard conceptual issues related to the notion of “cognitive enhancement” and then continues from a purely descriptive point of view by briefly reviewing some empirical aspects and sketching the current situation. Several enhancement strategies are being tested and used. Then the chapter offers some reflections on the treatment or enhancement distinction. It turns to normative issues by describing standard topics in current debates, then highlighting three examples of relevant novel questions under an ethical perspective. It is of central importance to be able to draw on long-term studies yielding data on the benefits, risks, and side-effects involved in the use of such substances over months and years. It concludes by making some general proposals for policy makers.

In Kenneth Einar Himma’s substantial commentary, there are a number of conceptual misunderstandings I want to get out of the way first. This will allow us to see the core of his contribution much clearer. On page 2, Himma writes about the problem of “explaining how it is that a particular phenomenal self is associated with a set of neurophysiological processes.” This philosophical question is ill posed: no one is identical to a particular phenomenal self. “Phenomenal self” must not be conflated with “me.” Under SMT, phenomenal selves, in standard situations, are highly specific forms of representational content. They are not particulars in an ontological sense. First, Himma introduces the notion of a “mental subject,” without giving any defining characteristics. He then proceeds to make a strong claim about conceptual necessity, presenting it as selfevident without an independent argument: “…it is not conceptually possible for a conscious mental state to occur that is not instantiated by a mental subject”. I must admit that I do not have this modal intuition, the point is not self-evident to me.

The representational dynamics of the brain is a subsymbolic process, and it has to be conceived as an "agent-free" type of dynamical self-organization. However, in generating a coherent internal world-model, the brain decomposes target space in a certain way. In doing so, it defines an "ontology": 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 the world, possesses an ontology too. It decomposes target space in a way that exhibits certain invariances, which in turn are functionally significant. A challenge for empirical research is to determine which are the functional regularities guiding this decomposition process. 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 the representational deep structure 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, we focus on the contribution the motor system makes to this process. As it turns out, 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 now clearly shows how the brain actually codes movements and action goals in terms of multimodal representations of organism-object relations. Under a representationalist analysis, this process can be interpreted as an internal representation of the intentionality relation itself. We try to show how such a more complex form of representational content, once it is in place, can later function as the building block for social cognition and a for more complex, consciously experienced representation of the first-person perspective as well. The motor system may therefore play a decisive role in understanding how the functional ontology of the human brain could be gradually extended into the subjective and social domains.