Thoreau’s audience is the townspeople who went to the lyceum to listen and to learn. These were adult people, continuing their education through a format that was just being explored. Thoreau’s audience were people who knew him already. Some of them (or many of them) saw the boy grow up. But this did not stop him from speaking his mind and writing and delivering lectures. Because for an artist, a true one, this is pure self-expression, unmuddled by the desire to be famous or get rich. This is what’s truly important.