Martin Flament Fultot

Open peer commentary on the article “Applying Radical Constructivism to Machine Learning: A Pilot Study in Assistive Robotics” by Markus Nowak, Claudio Castellini & Carlo Massironi. Upshot: I argue that the authors miss an important distinction between realism and representationalism. Because of this, their diagnosis of the current state of machine learning is valid, but for the wrong reasons. As a consequence, their approach to upper limb prosthetics may not be a step in the right direction.

It is widely believed that neural elements interact by communicating messages. Neurons, or groups of neurons, are supposed to send packages of data with informational content to other neurons or to the body. Thus, behavior is traditionally taken to consist in the execution of commands or instructions sent by the nervous system. As a consequence, neural elements and their organization are conceived as literally embodying and transmitting representations that other elements must in some way read and conform to. In opposition to this conception, growing approaches such as enactivism and ecological psychology hold that neurons are not in the business of representing. However, by insisting that neural causation is not of a representational kind, these anti-representationalist approaches seem to be left with only one rather implausible alternative, viz. that behavior is the result of nothing but basic physical causation such as push-pull forces. In this paper it is argued that a third form of causation—termed “modulation”—exists and is at work in the coordination of animal behavior. Modulation is the quasi-direct guidance of dynamical systems through specific yet emerging trajectories. By setting the constraints that coordinate the free interaction of multi-element systems, modulation influences without forcing nor representing goal states. The basic properties of modulatory causation are analyzed and shown to be present in some fundamental aspects of neural and bodily interaction.

A recent debate concerning the representational content of DNA in developmental processes has opposed “dynamicists” and “computationalists.” I review the arguments in favor of a representational interpretation of the role of genes, and show that they are inconclusive. There is a very restricted sense in which genes can be said to represent something, and stronger claims about DNA being a program for the construction of an organism are overstatements. I also show that arbitrariness, taken by representationalists to be a central criterion for identifying representational vehicles, is neither a sufficient nor a necessary condition to qualify as a representation. Finally, I propose a relatively new way to define what programs are, which implies that genetic regulatory networks shouldn’t be thought of as being programs. As a consequence, insofar as cognition and development share similar mechanisms, any computational account of cognition should be significantly weakened.