Final answer:
Yeats' phrase "To know they dreamed and are dead" encapsulates the fleeting nature of life and the enduring impact of the dreams of those who have passed away, particularly in the historical context of the Irish revolutionaries.
Step-by-step explanation:
William Butler Yeats' phrase "To know they dreamed and are dead" reflects on the idea that those who were once full of dreams and aspirations are now gone, having passed away. It suggests a contemplation of mortality and the transient nature of life and human ambitions.
In the context of Yeats' work, particularly in poems like 'Easter, 1916,' this reflection is intertwined with the fate of the Irish revolutionaries. These individuals dreamed of a free Ireland, but their lives were cut short by execution after the failed uprising against British rule. Their dreams, though potent, ultimately led to their deaths, leaving behind a legacy of both inspiration and sorrow.
Yeats often grapples with the themes of dreams, mortality, and the impact of cultural ideology on society. The phrase in question reverberates with the notion that dreams can serve an important purpose, they can be deeply influential, but they also carry the risk of loss and suffering.
It is a poignant reminder of human frailty and the permanent imprint of one's aspirations on the collective memory, despite individual mortality.