Get out the microscope, because we’re going through this poem line-by-line.
I was of three minds,
Like a tree
In which there are three blackbirds.
- This section plays with the common idiomatic expression, "I was of two minds," meaning torn between two choices or opinions. As in, "I was of two minds about whether to the gym that day." But with three minds, things just start getting ridiculous. It sounds less like indecisiveness and more like split personality disorder.
- The humor here is that Stevens takes an expression that people rarely think about in concrete terms and compares it with a very specific image of three birds in a tree. The possibilities of what this simile could mean are unlimited, so don't feel like you're missing out on the "right" explanation. Each blackbird seems to correspond to a different state of mind, but by itself this doesn't tell us much.
- The second section introduces the first person into the poem. He seems to be recounting a memory, and the external landscape moves into his mind.