A Traditional Scientific Perspective on the Integrated Information Theory of Consciousness

Abstract

This paper assesses two different theories for explaining consciousness, a phenomenon that is widely considered amenable to scientific investigation despite its puzzling subjective aspects. I focus on Integrated Information Theory (IIT), which says that consciousness is integrated information (as ϕ^Max) and says even simple systems with interacting parts possess some consciousness. First, I evaluate IIT on its own merits. Second, I compare it to a more traditionally derived theory called Neurobiological Naturalism (NN), which says consciousness is an evolved, emergent feature of complex brains. Comparing these theories is informative because it reveals strengths and weaknesses of each, thereby suggesting better ways to study consciousness in the future. IIT's strengths are the reasonable axioms at its core; its strong logic and mathematical formalism; its creative "experience-first" approach to studying consciousness; the way it avoids the mind-body ("hard") problem; its consistency with evolutionary theory; and its many scientifically testable predictions. The potential weakness of IIT is that it contains stretches of logic-based reasoning that were not checked against hard evidence when the theory was being constructed, whereas scientific arguments require such supporting evidence to keep the reasoning on course. This is less of a concern for the other theory, NN, because it incorporated evidence much earlier in its construction process. NN is a less mature theory than IIT, less formalized and quantitative, and less well tested. However, it has identified its own neural correlates of consciousness (NCC) and offers a roadmap through which these NNCs may answer the questions of consciousness using the hypothesize-test-hypothesize-test steps of the scientific method.

Keywords: artificial intelligence; causal structure; evidence; inductive versus deductive inference; mind-body problem; neural correlates of consciousness; neurobiological naturalism; neuroevolution; recurrent interactions; scientific theory/method; theories of consciousness.

Figure 1

Comparing Integrated Information Theory (A) and the Neurobiological Naturalism Theory (B), especially in how they were constructed. IIT is a deductive theory built from axioms, whereas NN is an inductive theory built primarily from observed evidence. IIT relies more on theory (T) and uses evidence (E) late, whereas NN uses evidence earlier and throughout. In IIT most of the steps are theory- or logic-derived, but in NN most steps are evidence-supported. Thus, I argue, IIT risks errors, in being more dependent on theory than on confirming evidence. Both of the theories, however, are scientifically testable, meaning they can be evaluated empirically at all of the “E” steps. They are also revisable, by new evidence derived from the tests (within limits). This revisability is shown by the blue arrows. The blue arrow for Neurobiological Naturalism is dashed to show that the later steps of this theory are still to be tested. NCCs: neural correlates of consciousness.

Figure 2

The Bull-Leaping Fresco from Minoan Crete, about 1450 BCE, as reconstructed by Émile Gilliéron. The original fragments make up less than half of it and they came from seven different wrecked panels at the archeological site of Knossos. Thus, though this reconstruction is vivid and looks coherent, one cannot tell how correct it is. Does this raise concerns about IIT, which also is based more on theory than evidence? Photo is in the public domain; see https://en.wikipedia.org/wiki/Bull-Leaping_Fresco. (accessed on 19 May 2021).

Figure 3

Further comparison of Integrated Information Theory and the Neurobiological Naturalism Theory, contrasting their conclusions. Furthermore, here is how the theories address the mind-body problem (or the “hard problem”): IIT nullifies the problem by starting with experience then incorporating the physical; NN is grounded in the physical, rejects all conceivability arguments, then says the problem of experience is scientifically manageable so it will be solved through the scientific method.