In it he proposes a five-stage hierarchy of consciousness:
0 : Inert (e.g. a rock)
1 : Hard Coded (e.g. protozoan)
2 : Learning (e.g. nematode)
3 : First Order Self (e.g. housefly). Where phenomenal consciousness, or subjective experience, begins. https://en.wikipedia.org/wiki/Consciousness#Types
4 : Second Order Selves (e.g. cat). Where access consciousness begins. Theory of mind. Self-awareness. Inner narrative. Anticipating the reactions of predator or prey, or navigating a social hierarchy.
5 : Third Order Selves (e.g. human). The ability to model the internal dialogues of others.
The paper claims to dissolve the hard problem of consciousness (https://en.wikipedia.org/wiki/Hard_problem_of_consciousness) by reversing the traditional approach. Instead of starting with abstract mental states, it begins with the embodied biological organism. The authors argue that understanding consciousness requires focusing on how organisms self-organize to interpret sensory information based on valence (https://en.wikipedia.org/wiki/Valence_(psychology)).
The claim is that phenomenal consciousness is fundamentally functional, making the existence of philosophical zombies (entities that behave like conscious beings but lack subjective experience) impossible.
The paper does not seem to elaborate on how to assess which stage the organism belongs to, and to what degree. This is the more interesting question to me. One approach is IIT: http://www.scholarpedia.org/article/Integrated_information_t...
The author's web site: https://michaeltimothybennett.com/