MCTB The Fundamental Perception Models
Related to the Non-Duality Model, and also useful for practice, are the Fundamental Perception Models. I say “models” because various traditions emphasize different qualities of reality as being essential. For instance, the Theravada uses the Three Characteristics of Impermanence, Suffering and No-Self, as you already know well by this point. The Mahayana traditions (Tibetans in particular), may emphasize Shunyata or emptiness, and the Vajrayana traditions may emphasize luminosity or the space-like meditative equipoise of Dzogchen. They may also talk about Maha Ati, or express fundamental truths in some other way.
These models may directly state or imply that enlightenment involves continuously perceiving these aspects of things in all sensations at a conscious level, so that every waking instant we were flooded with the sense of impermanence or luminosity or whatever as our dominant experience. While attempting to perceive this at all times is excellent practice advice, particularly when on retreat, were these models true then realization would seem to involve flooding the consciousness of the individual with a ton of information at all times. While there may be moments or bursts of this sort of perception in enlightened individuals, this is not what finally happens. Instead, with strong awareness of how things are, a process of identification stops, the switch is thrown, as noted above in the Non-Duality Models. By following the practice advice of the Fundamental Perception Models we may come to stop this process.
However, as the Buddha said, do not imagine that you must continue to carry the boat once you have crossed the river. While enlightened individuals can at a whim notice the true aspects of sensations, just as color is clear to a person with good eyesight (assuming they are not color-blind), so these things are clear to an enlightened being to various degrees as they progress along the path. That said, just because one can perceive something doesn’t mean that particular aspect is the dominant aspect of consciousness at all times. In short, the Fundamental Perception Models are very useful for practice, but do not quite accurately describe the final result.