If the Thoreau quote in question is, "Things do not change; we change," then I believe that a firm case can be made for its connection to the film, Dead Poets Society. Through Mr. Keating's teachings the boys recognize that they are the agents of change in both themselves and the world. Welton Academy will remain, as demonstrated in the ending, when Nolan instructs them on the mathematical formula for determining a poem's value, something that the boys had to tear out of their books because of Keating. The threshold of revelation comes when the boys stand on their desk to their departed teacher, calling out, "O Captain, My Captain!" It is this moment when the boys recognize that they have changed and while the institution will continue in its traditionalist ways, they are the agents of change that will always strive to "seize the day." In this moment, the boys have lived out Thoreau's quote of people being the agents of change while institutions might not be so receptive to such elements. It is an autonomous philosophy that embraces individual freedom and action, something that Mr. Keating had sought to impart in them throughout the course of the film.