Exteroception organs

The exteroceptive organs constitute a model of a whole system of consciousness. First, they are active organs, while all of them can respond to stimulation when they are passive, as when a light is suddenly shined in your eye, they normally engage in an active scanning of the environment. Your eyes dart about you turn your head or perk up your ears to hear sounds more clearly you reach out to touch things that interest you. Similarly, consciousness can be passively stimulated, but ordinarily it is an active process. 

The subsystem Exteroception includes the classical sense organs for registering changes in the environment eyes, ears, nose, taste organs, and touch organs. 

Second, each of the classical exteroceptive sense organs has limited responsiveness. The eye cannot respond to ultraviolet light, the ear cannot pick up sounds above or below certain frequencies, touch cannot respond to exceptionally subtle stimuli. Similarly, any state of consciousness has certain limits to what it can and cannot react. 

Third, you have some voluntary control over the input to your exteroceptive sense organs, if you do not want to see something, you can look away or close your eyes if you do not want to hear something, you can move away from the sound source or put your fingers in your ears, in any state of consciousness, you have some voluntary control over exteroceptive functioning. But the control is limited if the sound is intense enough, it is difficult not to hear it at all, even with your hands over your ears. 

Although many changes in perception of the external environment are reported in d-ASCs, these usually do not represent changes in the exterocepters themselves, except possibly in some drug-induced d-ASCs. Each of the classical sense organs is a masterpiece of engineering it is already as sensitive as it can be. Thus its useful sensitivity is... 

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