In Brueghel's painting, the fall of Icarus is happening in the back; no one is even noticing it. Brueghel's painting shows that how a tragedy may not even be noticed by those who are not directly affected by it.
Auden translates Brueghel's painting a little differently, however. To Auden, the fall of Icarus IS being noticed by the plowman and the sailor; Auden says that they are too busy to deal with the disaster and get on with their work. Auden says that Icarus falling is "not an important failure" to them.
Auden's interpretation of the painting is therefore much more negative than Brueghel's initial work.
