Hard criteria for empirical theories of consciousness

Abstract

Consciousness is now a well-established field of empirical research. A large body of experimental results has been accumulated and is steadily growing. In parallel, many Theories of Consciousness (ToCs) have been proposed. These theories are diverse in nature, ranging from computational to neurophysiological and quantum theoretical approaches. This contrasts with other fields of natural science, which host a smaller number of competing theories. We suggest that one reason for this abundance of extremely different theories may be the lack of stringent criteria specifying how empirical data constrains ToCs. First, we argue that consciousness is a well-defined topic from an empirical point of view and motivate a purely empirical stance on the quest for consciousness. Second, we present a checklist of criteria that, we propose, empirical ToCs need to cope with. Third, we review 13 of the most influential ToCs and subject them to the criteria. Our analysis helps to situate these different ToCs in the theoretical landscapeand sheds light on their strengths and weaknesses from a strictly empirical point of view.

Predictive processing as a systematic basis for identifying the neural correlates of consciousness

“…Of course, we are not here placing all these diverse theories on the same footing with respect to how they conceive such uncertainty reduction. Different theories propose diverse and often incompatible mechanisms, operating at quite different spatiotemporal and even conceptual scales (for discussion, see Doerig et al, 2020;Graziano et al, 2020).…”

‘Orch OR’ is the most complete, and most easily falsifiable theory of consciousness

“…Reduced brain volume and normal function Figure 3 in Doerig et al (2020) shows the brain of a person with markedly reduced brain volume, but normal cognition and consciousness. Brain compensation by neuronal and synaptic plasticity directly requires microtubules.…”

Is predictive processing a theory of perceptual consciousness?

“…Hobson and Friston (2014, p. 22) boldly assert that consciousness "is not a hard thing to understand, describe, or make hypotheses aboutif one associates it with inference based on deeply structured hierarchical (probabilistic) beliefs about sensations"; Wiese and Metzinger (2017, p. 2) claim that if the PP theory is on the right track, "it may provide the means to build new conceptual bridges between theoretical and empirical work on cognition and consciousness"; Clark, Friston and Wilkinson that their version of the PP story attempts to "lay the groundwork for a substantive, but revisionary, account of consciousness itself" (Clark et al, 2019, p. 20);and Drayson (2017, p. 8) that on the PP approach, "conscious perceptual experience is the product of the entire prediction minimization process: it is determined by the interactions between top-down and bottom-up information flow within the entire hierarchy". Perhaps most significantly, Doerig et al (2020) include PP theory in their list of most influential currently debated theories of consciousness. Assessing the extent to which consciousness is systematically related to the explanatory moves of a PP theory, the central task of this paper, thus seems to be a worthwile exercise.…”