For the congenital blind, because he has never experienced any color experience at all, there is no concept of color and no "seeing" for him, because he has no experience of seeing. As for his personal experience (such as nerve stimulation) in the visual part of his brain (if any), it is different from the visual experience (concept) of normal people and cannot be confused. For him, there is no color of "seeing", not even "seeing".

For the acquired blind person, because he has experienced color, he certainly has the concept of color. Although he can't "see" (meaning to get visual information from the usual visual channels), as long as the visual part of his brain is still normal, he will feel the color under some stimulus. Generally speaking, because he can't get visual information from the usual visual channels, it's a bit like not receiving any light, so his visual experience is a bit like being in the dark-"seeing" (feeling) black. But if the visual part of his brain is stimulated (if it is not damaged) to make him have vision, then he will have a sense of color-"seeing" (feeling) color.

Therefore, the statement that "blind people live in a dark world" is not entirely appropriate in science, but can only be said to be a statement of goodwill and sympathy for people.

Famous blind people include: internationally famous blind singer Ray Charles, China folk artists A Bing, Lola, Helen Keller and other American writers.