In his poem “Ode on a Grecian Urn,” John Keats calls the urn a “foster child of silence and slow time.” Let's unpack this description and reflect on its meaning.
First, a foster child refers to a child who is raised by adults who are not their biological parents. The word “foster” suggests a nurturing that leads to growth and development. When Keats says that the urn is a foster child of silence and time, then, he means that the urn was not created by silence and time (for it was made by a human artist). Rather, silence and time have contributed to the urn's growth and development in some way.
It seems a little odd to think of an inanimate object like an urn growing and developing, and of course, it cannot do so physically. But it does grow and develop in meaning and value over time. Later in the poem, Keats describes the glimpse the urn provides of a history that is lost to the modern world yet has grown in meaning because of its remoteness. Over the years, the urn has become a valuable object for what it shows us about the past, and it provides meaningful images not available elsewhere.
Now let's think about silence and “slow time” and how these add meaning and value to the urn. Silence gives a nod toward observation and reflection. Only in silence, without distraction, can a viewer fully encounter the images on the urn and discern or create their meaning. Time, as mentioned above, makes the urn more remote from us and therefore a source of history. Further, time has left this urn intact. Many such objects once existed but no longer do, but time has spared this urn, allowing it the opportunity to speak to us today.