Three things that were important to Thoreau were philosophy and independence, books, and his writings. Thoreau needed independence to pursue his study of nature. Also, to have a mind that was free, clear, and original. Books were also important to him. As a Harvard graduate, he thought education does not come to an end when you graduate. He continued reading serious literature for the rest of his life. His writings were also of great importance to him. Writing is a form of thinking; thus, his writings might be a part of his philosophy.
