Theories have always played a central role in consciousness science, owing, in part, to the field being situated at the intersection of philosophy, psychology, and neuroscience. The proposals of several prominent theories of consciousness -- which remain influential today -- including Global (Neuronal) Workspace Theory (GWT/GNWT)3, Integrated Information Theory (IIT)4, and Recurrent Processing Theory5 around 20-25 years ago helped build a strong community of researchers who conduct empirical or theoretical work on consciousness. Today, there are about five popular theories of consciousness, including the above three, along with higher-order theory6 and predictive processing theory7,8.
What is a theory? Theory is defined as a plausible principle or body of principles to explain a phenomenon. A theory should be simplifying (otherwise it would not help with understanding) and have predictive power (otherwise it would be useless). A theory does not have to be comprehensive (e.g., a psychological theory does not have to specify neural implementation). A theory should have a clearly outlined explanatory scope (i.e., the target phenomenon it aims to explain). Finally, a theory should be testable in the sense that it can generate falsifiable hypotheses.
Theory is often confused with framework. Framework is a way to organize concepts, a way to think about a phenomenon. A framework tends to be broader than a theory and may or may not be directly testable. For instance, Marr's three levels of description (computation, algorithm, implementation) is a framework that has been extremely useful in cognitive science and neuroscience. A good example in consciousness science is the idea that sensory processing can be subliminal, preconscious, or conscious, which is a framework. By contrast, the idea that conscious access has the constituent mechanism of sensory information crossing a nonlinear bifurcation threshold (GNWT) is a theory. Viewed in this light, IIT, at least in its original formulation, might be called a framework, because it is notoriously difficult to test but provides broader perspectives that can be quite helpful for thinking about consciousness and especially its enabling conditions (for instance, the idea that consciousness has both integration and differentiation -- both a unified experience and a rich repertoire). When I proposed the Joint Determinant Theory (JDT) in 2023, I deliberately labeled it a framework because it offers a way to think about the neural basis of consciousness: a state-space view and the idea that the specific circuit mechanisms underlying different aspects of conscious content can be different; nevertheless, I retained "theory" in the name with the hope that over time it becomes specified with detailed neural mechanisms that are directly experimentally testable and the thinking that many contemporary "theories" are equally vague.
Compared to other disciplines in neuroscience and psychology, theories have played an outsized role in consciousness science. Empirical studies in this domain, and even grant proposals, are often expected to make contact with existing theories. Recently, $20-30 million was invested by Templeton World Charity Foundation in five adversarial collaboration projects carried out by large, international consortia to pit theories against each other. Sociologically, the few dominant theories have perhaps become entrenched, with young consciousness researchers often aligned with one of the camps. Pitfalls of this state of affairs have been pointed out recently, including confirmation bias that appears commonplace.
What is the best way forward? Some may advocate for empirical studies to ditch theories altogether. There are certainly great opportunities for theory-neutral empirical studies to contribute, especially at this (still young) stage of development of the field. But it is also important to remember that "experiment without theory is blind". With that in mind, here I advocate for a middle-of-the-road, nuanced approach.