The poem opens with a bleak claim: in the relationship between master and slave, nobody is free of hatred. Slaves resent their masters and themselves, while masters despise everyone, including everything beyond the two groups. From there the speaker widens the view to a whole culture drifting numbly toward disaster, with a "glacial surface" creeping across our shared imagination while the world burns.
Then the tone turns to questions. The speaker asks whether we really look at ourselves in mirrors and windows, or whether we flinch. We are told that what we see is just one object among countless others, and that there is a faint "tremor" of horror at the edge of thought, which we choose to ignore. The final image is the most striking: we smash the mirror, and the shards cut our own hands. The speaker's mood is accusing but weary, even a little despairing. The last line leaves no escape, since the blame sits with us.