The importance of Westward Expansion is vital in the American imagination of pushing out the boundaries of territory and exploring new areas, "civilising" them and claiming them. Jody's grandfather is right in a sense that once they hit the sea, that was it, in terms of the way in which they had reached the limits of unknown territory to explore:
The old man smiled. "There's no place to go. There's the ocean to stop you. There's a line of old men along the shore hating the ocean because it stopped them."
However, Jody's stubborn insistence that there need be no borders to such an adventuring and heroic spirit points towards the theme of the story and the wider symbolic meaning of expansion and heroism. Jody's grandfather is one of those men along the shore "hating the ocean because it stopped them," whereas Jody argues that geographical boundaries need not limit such a spirit of adventure and heroism. Many unknown territories still existed after America was entirely settled, including more metaphysical realms such as the quest for justice, racial equality and peace. Jody's grandfather is therefore wrong in one sense: all of us need new aims and goals to motivate us and inspire us, and the lack of geographical territory to explore only means that new arenas must be found.