Hmm, I don't agree with your ranking. Each sense has a range of tasks that it covers, and although there's some overlap, each sense covers things that simply ca

Hmm, I don't agree with your ranking. Each sense has a range of tasks that it covers, and although there's some overlap, each sense covers things that simply can't be replaced by the others. Therefore they are all dependent. Sight allows highly detailed sensing of the nearby environment. Smell gives a longer range detection, plus sensitivity to chemical differences which sight lacks. Taste gives a more specific chemical test to things we're about to eat. Touch provides some sensory information about the environment, but mostly it's a control for our manipulation of the world. It facilitates tool-building. Hearing facilitates high-bandwidth information transfer (language) as well as covering some mid-range distance sensing duties for cases where our smell and sight are lacking. I think ranking these is futile, since they all cover such manifestly different use-cases.