Hemingway employs a direct, unadorned style of writing in order to

Hemingway employs a direct, unadorned style of writing in order to allow the reader to draw his or her own conclusions.
His style is very journalistic, including short words with no embellishments, simple grammar, and everyday speech. Whereas other writers tried to employ very elaborate styles and vocabulary, Hemingway did quite the opposite in order to make his audience think for themselves instead of being spoonfed the answers.