Do blind people know what sight is?

Do blind people know what sight is? How on earth do you explain sunsets, fireworks, darkness and brightness to a person who lacks the ability to experience it?

How do you explain life to the living dead? Do they even know that they are not really alive?

Sometimes, I want to scream the gospel from the top of my lungs until either when my lungs collapse, or when my annoyed listener finally gets it. Then I realize, deaf people can't hear. Blind people can't see. Dead people can't do anything.

Oh God, they need a miracle. Please, awaken their senses, and resuscitate their souls. And may my voice and lungs not give out for a long long time.