Sum: Forty Tales from the Afterlives message of the book is the importance of exploring new ideas beyond the ones that have been traditionally passed down. The title word "Sum" refers to the Latin for "I am," as in "Cogito ergo sum". Like Italo Calvino's "Invisible Cities", "Sum" does not fit entirely into the traditional category of a novel. "Sum" has been called "philosofiction", an "experimental novel", and "a collection of thought experiments". Most of the stories are understood to "posit the afterlife as mirroring life on Earth" The New York Times Book Review called Sum a "delightful, thought-provoking little collection [which] belongs to that category
Mr. Cogito Cogito and Pure Thought"), "Pan Cogito czyta gazetę" ("Mr. Cogito Reads A Newspaper"), "Pan Cogito a ruch myśli" (" Mr. Cogito and the Motion of Thought"), "Domy przedmieścia" ("Houses On The Outskirts Of The City"), "Alienacje Pana Cogito" ("Mr. Cogito's Alienations"), "Pan Cogito obserwuje zmarłego przyjaciela" ("Mr. Cogito Watches a Deceased Friend"), "Późnojesienny wiersz Pana Cogito przeznaczony dla kobiecych pism" ("Mr. Cogito's Late Autumn Poem For Women's Magazines"), "Pan Cogito rozważa różnice między głosem ludzkim a głosem przyrody" ("Mr. Cogito Considers the Difference Between the Human Voice And The Voice of Nature"), "Pan Cogito biada nad małością snów" (Mr. Cogito