I’ve both understood and been completely mystified by Dickinson’s use of dashes since meeting her voice in high school. Finally, FINALLY, someone makes sense of it for me, in terms of how writers can manipulate syntax to create meanings, contradictory meanings, and multiple meanings all with the same few words.

from “What Dickinson Makes a Dash For” in Broken English:

Dickinson uses the dash to avoid semantic mono-determination: a dash occurs where the more exclusive choice (of period or comma or colon or semicolon) would direct the sentence to a single end. Because her semantics are multiplicative her syn-tactics need to be flexible, especially at the junctures. The same dash may operate in one reading as a period or semicolon, distinguishing what precedes from what follows it; and in another, only a blink of an eye away (and existing all the while in the text) as a sign of resemblance instead, a colon, for instance. Only by suspending the power of the period (definer and difference-maker in the prose sentence) can Dickinson interweave phrases the way she does, release meaning from the sentence’s exclusionary powers, and nudge the whole occasion toward that at-onceness which is her manifold temporality.