Among other sources, Ligotti cites Peter Wessel Zapffe's essay "The Last Messiah" and the writings of Emil Cioran (1911–1995) and Philipp Mainländer (1841–1876) as inspirations for his philosophical outlook.

This makes consciousness something that "should not be," and humanity's attempts at either coping with, ignoring, or actively suppressing this fact drive a significant portion of modern society's obsessions, such as the quest for healthy living (despite the fact that everyone dies regardless), art and horror (as acts of sublimation), and the desire to have children (as a futile attempt at a form of genetic immortality), among many other common behavioral norms.

Philosophical pessimism is not held or even widely considered by most humans, which, according to Ligotti, is because of its terrifying implications rather than the strength of the arguments for or against it.This is the tragedy: Consciousness has forced us into the paradoxical position of striving to be unselfconscious of what we are—hunks of spoiling flesh on disintegrating bones.

W. Scott Poole of PopMatters praised Conspiracy's "astonishing range", saying that "Ligotti takes us on a tour of both philosophy and literature that manages to include Schopenhauer, Ann Radcliffe, Thomas De Quincey, H.P.

[6] In 2014, the HBO television series True Detective attracted attention from some of Ligotti's fans because of the striking resemblance between the pessimistic philosophy espoused in the first few episodes by protagonist Rust Cohle (played by Matthew McConaughey) and Ligotti's writings in The Conspiracy Against the Human Race,[7] leading to accusations that dialogue from Cohle's character in True Detective were plagiarised from The Conspiracy Against the Human Race.