Dualism is defined as two independent and opposing parts, where one is often good and the other evil. The two are perceived as irreconcilable and/or one precludes the other. Dualistic thought is evident throughout the book, and is even visible in the deliberately cryptic title The Left Hand of Darkness , which leaves out the other half of the riddle, stated in the Gethenian poem Tormer’s Lay, that Estraven cites on the mountain three-fourths through the novel:
"Light is the left hand of darkness and darkness the right hand of light
Two are one, life and death, lying together like lovers in kemmer, like hands joined together, like the end and the way."
Here, the dualism and contrary image-sets that runs as an undercurrent