Higher-Order Thought Theory (HOTT) posits that a mental state becomes conscious only when accompanied by a separate, higher-order thought about that state. According to HOTT, lower-order states—like a raw sensory perception or an emotion—are completely unconscious on their own. Consciousness arises exclusively when the mind generates a distinct, meta-representation that target-monitors the lower-order state, effectively representing oneself as being in that specific mental condition at that moment.

Other Resources:
https://en.wikipedia.org/wiki/Higher-order_theories_of_consciousness
https://plato.stanford.edu/entries/consciousness-higher/

Integrated Information Theory (IIT) posits that consciousness is a fundamental property of physical systems, determined by their capacity to integrate information. Consciousness is measured by phi which is the degree to which a system’s cause-effect power is irreducible to its individual parts. The theory asserts that consciousness exists wherever a system forms a unified, highly differentiated whole, and the specific quality of an experience is identical to the complex, multidimensional mathematical geometry of that integrated network.

Other Resources:
http://www.scholarpedia.org/article/Integrated_information_theory
https://en.wikipedia.org/wiki/Integrated_information_theory

Does Integrated Information Theory (IIT) feel too woo-woo to anyone?
byu/Prestigious_Hope2082 inconsciousness

Global Neuronal Workspace Theory posits that consciousness occurs when localized sensory signals cross an attentional threshold and “ignite” a central, long-distance frontoparietal network. Once inside this workspace, the information is globally broadcast back to otherwise isolated brain modules. This widespread broadcasting synchronizes the neural network, making the data simultaneously available to multiple systems—such as working memory, emotional evaluation, motor planning, and verbal report—creating a unified conscious experience.

Other Resources:
https://en.wikipedia.org/wiki/Global_workspace_theory