“‘Tis” is an archaic combination of “it is.” When this pronoun-verb combination appears at the beginning of a sentence to introduce another noun, a rhetorical emphasis is placed on that noun. In this example, by saying “‘Tis the Majority,” the speaker emphasizes the importance of the “Majority” in the subsequent lines.
“This” is a demonstrative pronoun, meaning a pronoun that refers to a fact, occurrence, or statement implied in previous context. In this way, “this” groups together the entire idea presented in the first few lines of this poem: that sense and madness are the same. However, the nature of Dickinson’s writing suggests that “this” might also be a poetic device called “deixis.” Deixis is the use of pronouns that have intentionally unclear referents which force the reader to interpret the subject of the line based on their understanding of the context. When read through a deictic lens, “this” thing that the majority prevails in is unclear; the emphasis of the line becomes the Majority’s power to prevail rather than the object that it controls.
The syntax of this line replicates the syntax of the first line. Because of this, we can read the first and third lines as complimentary inversions of each other: madness is the divinest sense, sense the starkest madness. “Starkest” in this context means the most powerful and authoritative. While both lines connect sense and madness to seemingly positive concepts, “starkest” is also defined as the most “impenetrable, harsh, and violent.” However, the negative connotations inherent to “stark” imbue the second claim with problematic double meanings: while madness is divine, sense can be seen as violently dangerous.
