So let's kick it off with not the first, but the second line of the piece: "Only dreams closing the day". And while it may just seem like semantics, the "Only" of this line is extremely important. It's not just "dreams closing the day", it's only dreams--specifically and irrevocably that one thing. This particular phrasing, laying emphasis not just on the dreams themselves but on the closing of the day, begins to point out the dramatically important theme--night is coming. Only dreams, the likes of which are associated with night, close out the day, lead to the night where the darkness rises and takes hold of the world.
The "gray things, the dark things" (line 3), come out then, to their "dreamland" (line 4)--their nightmarish twist on reality that not only feeds on the darkness, but feeds the darkness, itself. These dark things, the inhabitants of the night, are representative of our fears--as all monsters are. They are symbolic of the pain and the unknown, of the insecurities and the wide chasm of distance between what is expected of us and what we actually find ourselves to be. This, Sandburg points out through the re-emphasis on dreams--which, okay, let's be honest, how many of us have found our broken dreams to be the biggest contributors to our nightmares. Who's to say that our fears of failure, our constant struggle to meet our own expectations, or even just to achieve what we expect to achieve, won't drive us into madness? Who's to say that we are impermeable to these things?
"Tears and loss and broken dreams / May your heart find at dusk".
And this is exactly what was mentioned before hand, but stated by Sandburg. Tears, both in the sense of tears cried and tears in the fabric of our plans. Loss, both of innocence to the darkness and dreams that have fallen apart. Broken Dreams, the once-brilliant hopes that lit our ways, dashed and outed until all that is left is what could have been--a very dangerous thing, indeed.
