“Maybe being outside is life itself, and everything else we do—working our jobs and living in the cities where those jobs are—is a sacrifice of the time we could be actually living, a sacrifice we make to pay our way in society. Karl Marx divided time into the realm of necessity and the realm of freedom, and nature is squarely in the second category. What makes our lives meaningful is that we eventually die; maybe what makes our time in nature meaningful is that eventually we have to go back to the office.”