The other day, when discussing a paper that criticized IIT (the Integrated Information Theory of consciousness) as unscientific, I noted that IIT, while questionable as the ultimate answer for consciousness, could be useful in the more limited capacity of distinguishing degrees of consciousness in a brain. Apparently I’m not the only one who thinks that, as this preprint paper from Matthias Michel and Hakwan Lau discusses: On the dangers of conflating strong and weak versions of a theory of consciousness.
The authors identify two versions of the theory:
Empirical IIT is the view that some measures of complexity of brain networks can be used to detect states of consciousness, i.e., whether subjects have subjective experiences (such as during wakefulness, or dreams), or not (such as being in a coma, anesthetized, or dreamless sleep). That is, Empirical IIT takes complexity to be a marker of consciousness.
…On the other hand, Fundamental IIT is the view that a specific form of complexity (integrated information) is identical with consciousness (Oizumi et al., 2014). That is, Fundamental IIT posits that a specific form of complexity is the constituent of consciousness. Specific conscious experiences are also exactly identified with specific states of a network with this particular form of complexity (Tsuchiya et al., 2015; Tsuchiya, 2017).
The authors see merit in the empirical version of the theory, but are “unsure” about the latter. This actually matches my own intuition pretty closely. It’s the metaphysical and somewhat magical aspects of the stronger “fundamental” theory that turn me off, the identification of consciousness with complexity, without attempting to wire up how that complexity, in and of itself, leads to specific percepts.
Anyway, the paper more broadly urges that researchers strive to define the NCC (neural correlates of consciousness) in terms of the markers of consciousness, what shows its presence, rather than as the constituents of consciousness, that is, in terms of the signs of consciousness rather than the identity of it. It’s a caution for epistemic humility.
And it reminds me why I have instrumentalist rather than realist leanings, that is, viewing scientific theories as pragmatic prediction tools rather than metaphysical statements of reality. When discussing Stanislas Dehaene’s theory in the previous post, I noted its promising value from an instrumental viewpoint, that is, one focused on predicting observations. Taking that view, we can find ways to productively combine theories like IIT, GWT (Global Workspace Theory), HOT (Higher Order Theory), and many others.
But if we take each theory in its strongest incarnation, one that asserts that what it describes is consciousness, then there can be only one. And I highly doubt there will be only one. The collection of cognitive capabilities that trigger our intuitions of consciousness are too complex and varied. Much like the difficulties in defining life (described by an Aeon article out today), we will almost certainly need many theories.
Unless of course I’m missing something.
(Via tweet by Hakwan Lau)