What does this quote by john steinbeck?

Question

"It is the responsibility of the writer to expose our many grievous faults and falures and to hold up to the light our dark and dangerous dreams, for the purpose of improvement"

Answer 1

He feels that a writer has the ability point out the flaws in our society so we may improve on those faults.

For example, in the early 1900s, muckrakers were writers that pointed out the problems in American society. After Upton Sinclair wrote the Jungle about the unclean conditions in Chicago meat factories, Teddy Roosevelt passed the Food and Drug Act to make factories clean and safe. Writers have the ability to give problems the attention they need, and bring them to a wide audience, so that they may be corrected.

Answer 2

It means that it is the artists' job to write about the truths (often the ugly truths) in society.  When writers bring a culture's "deep dark secrets" to our attention, we can address the problem and improve individually and collectively.