Materialism: claims that consciousness is a wholly physical phenomenon. Conscious experiences are states of the physical world—typically brain states—and the properties that make up the phenomenal character of our experiences, known as phenomenal properties, are physical properties of these states. For example, a materialist might claim that the experience of seeing a red tulip is a particular brain state and that the “redness” of the experience is a feature of that state.
Property dualism: denies materialism, claiming that phenomenal properties are non-physical properties. Unlike substance dualism, this view claims that there is just one sort of substance or entity while asserting that it has both physical and phenomenal properties. The “redness” of the experience of seeing the tulip may be a property of the brain state involved, but it is distinct from any physical property of this state.
Panpsychism: claims that phenomenal properties, or simpler but related “proto-phenomenal” properties, are present in all fundamental physical entities. A panpsychist might claim that an electron, as a fundamental particle, has either a property like the “redness” of the tulip experience or a special precursor of this property. Panpsychists do not generally claim that everything has conscious experiences—instead, the phenomenal aspects of fundamental entities only combine to give rise to conscious experiences in a few macro-scale entities, such as humans.
Illusionism: claims that we are subject to an illusion in our thinking about consciousness and that either consciousness does not exist (strong illusionism), or we are pervasively mistaken about some of its features (weak illusionism). However, even strong illusionism acknowledges the existence of “quasi-phenomenal” properties, which are properties that are misrepresented by introspection as phenomenal. For example, an illusionist might say that when one seems to have the conscious experience of seeing a red tulip, some brain state is misrepresented by introspection as having a property of phenomenal “redness”.
Functional theory: Theories that think of consciousness as ultimately a form of computation.
IIT: Functional theory. Though they believe consciousness needs embodiment. “The same way a computer can simulate the weather and rain, it’s not causal, ****it can’t make it rain”. Phenomena being causal seem to be a central thing in the theory.
Conversely, for IIT, the beating heart of consciousness is intrinsic causal power, not computation. Causal power is not something intangible or ethereal. It is very concrete, defined operationally by the extent to which the system’s past specifies the present state (cause power) and the extent to which the present specifies its future (effect power). And here’s the rub: causal power by itself, the ability to make the system do one thing rather than many other alternatives, cannot be simulated. Not now nor in the future. It must be built into the system.
Consider computer code that simulates the field equations of Einstein’s general theory of relativity, which relates mass to spacetime curvature. The software accurately models the supermassive black hole located at the center of our galaxy. This black hole exerts such extensive gravitational effects on its surroundings that nothing, not even light, can escape its pull. Thus its name. Yet an astrophysicist simulating the black hole would not get sucked into their laptop by the simulated gravitational field. This seemingly absurd observation emphasizes the difference between the real and the simulated: if the simulation is faithful to reality, spacetime should warp around the laptop, creating a black hole that swallows everything around it.
The above is by Cristof Koch, one of the most reasonable proponents of the area. I think it’s a very weak and weird argument. IIT has been criticized by more than 140 scientists of the consciousness area by being accused to be pseudoscience.
It proposes that consciousness emerges from the way information is processed within a ‘system’ (for instance, networks of neurons or computer circuits), and that systems that are more interconnected, or integrated, have higher levels of consciousness.
Above is also Cristof Koch in a different article, defining IIT in a way I quite like. Though, I fail to find more backing for this claim.
The easy problem: David Chalmers coined the “easy and hard problems” term. The easy is identifying the neural correlates and mechanisms that enable cognitive functions and behaviors associated with consciousness.