Photo source: Wikimedia Commons, National Portrait Gallery
Hellen Keller (1880-1968) was an American writer and political activist. Mark Twain wrote in a letter to Keller,
"I am charmed with your book - enchanted. You are a wonderful creature, the most wonderful in the world - you and your other half together - Miss Sullivan, I mean, for it took the pair of you to make a complete and perfect whole." (1903)
The rest of this post is some quotes from Keller.
Optimism
"Optimism is the faith that leads to achievement; nothing can be done without hope." (Optimism, 1903)
"To know the history of philosophy is to know that the highest thinkers of the ages, the seers of the tribes and the nations, have been optimists." (Optimism, 1903)
Tolerance
"Tolerance... is the greatest gift of the mind; it requires the same effort of the brain that it takes to balance oneself on a bicycle." (The Story of My Life, 1903)
"The heresy of one age becomes the orthodoxy of the next. Mere tolerance has given place to a sentiment of brotherhood between sincere men of all denominations." (Optimism, 1903)
Senses
"It seemed to me that there could be nothing more beautiful than the sun whose warmth makes all things grow." (The Story of My Life, 1903)
"I who cannot see, find hundreds of things to interest me through mere touch." (Three Days to See, 1933)
"Use your eyes as if tomorrow you would be stricken blind. And the same method can be applied to other senses. Hear the music of voices, the song of a bird, the mighty strains of an orchestra, as if you would be stricken to deaf tomorrow." (Three Days to See, 1933)