Refuting the unfolding-argument on the irrelevance of causal structure to consciousness.

The unfolding argument (UA) claims that if consciousness depends on causal structure, its presence is unfalsifiable because any input-output function of a recurrent neural network can be approximated by an equivalent feedforward network, making behavioral tests inconclusive. This paper refutes UA by showing that the Universal Approximator theorem does not support robust functional equivalence between feedforward and recurrent networks, and that such equivalence would only apply to static input-output functions, not temporal patterns or responses to structural perturbations. Evidence from cognitive neuroscience indicates that consciousness involves flexible behavioral control requiring interacting top-down and bottom-up processes in brain dynamics, which recurrent networks can capture but feedforward networks cannot.

Study at a glance

Abstract

The unfolding argument (UA) was advanced as a refutation of prominent theories, which posit that phenomenal experience is determined by patterns of neural activation in a recurrent (neural) network (RN) structure. The argument is based on the statement that any input-output function of an RN can be approximated by an "equivalent" feedforward-network (FFN). According to UA, if consciousness depends on causal structure, its presence is unfalsifiable (thus non-scientific), as an equivalent FFN structure is behaviorally indistinguishable with regards to any behavioral test. Here I refute UA by appealing to computational theory and cognitive-neuroscience. I argue that a robust functional equivalence between FFN and RN is not supported by the mathematical work on the Universal Approximator theorem, and is also unlikely to hold, as a conjecture, given data in cognitive neuroscience; I argue that an equivalence of RN and FFN can only apply to static functions between input/output layers and not to the temporal patterns or to the network's reactions to structural perturbations. Finally, I review data indicating that consciousness has functional characteristics, such as a flexible control of behavior, and that cognitive/brain dynamics reveal interacting top-down and bottom-up processes, which are necessary for the mediation of such control processes.