Consciousness arises when three processes operate together: continuous generation of interoceptive feelings (experiencing the body's internal state), continuous production of sensory images from the organism's perspective, and a combination of these into subjectivity about those images. The biological basis involves peripheral and central interoceptive and exteroceptive physiology for the first two components, while the third depends on integration across the spinal cord, brainstem, diencephalic nuclei, and mesial cerebral cortices.
Consciousness arises when mental contents like perceptions and thoughts are automatically identified as belonging to a specific organism. This identification is provided by a continuous flow of homeostatic feelings—sensations such as hunger, pain, well-being, or the feeling of being alive—that stem from the body's life-regulation processes. These feelings were the first conscious phenomena in evolution, selected because they gave organisms overt guidance for survival. Feelings emerge from interactions between the nervous system and nonneural body components like viscera and circulating chemicals, offering a solution to the mind-body problem by making feelings the mental version of bodily processes.