The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far.

These lines, the first of Section I, establish the frightening nature of the unknown right from the beginning of the story. While gaining knowledge may seem advantageous, Thurston emphasizes that remaining ignorant about the world’s expansiveness is the key to living a comfortable life. This quotation also serves as foreshadowing for the horrifying discoveries Thurston will eventually make, and it creates suspense for the reader by hinting at what remains unknown to them about the direction and contents of the story itself.

Who knows the end? What has risen may sink, and what has sunk may rise. Loathsomeness waits and dreams in the deep, and decay spreads over the tottering cities of men.

This quotation comes from the final paragraph of the story as Thurston reflects on the possibility that Cthulhu will still return to rule the earth. His speculation contains anxiety about the future, emphasizing the impossibility of predicting things that have not yet occurred. The idea that “what has sunk may rise” also alludes to the notion that humans are powerless to prevent Cthulhu from waking up as fate is in control. All of the details included in these last lines work to create a dark and horrifying picture of what may lie ahead.