When we say changing states, we are referring to much more than the dramatic states created by LSD, isolation tanks, REM sleep, etc. We are also including normal states of consciousness, which we can imagine as kindled default settings' of our various modalities. When any one of these settings returns to one of its default settings, it will, we conjecture, tend to entrain all the other modalities to the settings they habitually take in that state. To accomplish this, we must suggest that each modality is connected to every other one. A sight, a smell, a sound, or a tactile feeling can all inspire fear.
Fear can motivate ideation.
Ideation can inspire arousal. Changes in affect can initiate alterations in introspection. Introspection alters affect. State specific settings of individual modalities could initiate settings for other modalities. Our main hypothesis here is that all these intermodal connections, operating as a single system, has a single phenomenological correlate.