When James first enters the Pontifex Institute, the camera lingers on a painting in the hallway. The painting shows the cabin in which the four hikers shelter at the start of the film.
One of the last films from Fox that was made before they were acquired by Disney. The film was quietly dumped into theaters and made so little money that even a home video release on DVD was deemed non-profitable.
Based on Cullen Bunn & Vanesa R. Del Rey's 'The Empty Man' comic series published by Boom! Studios.
When James is researching on Wikipedia, much of the text on "Tulpas" and "thoughtform" is genuinely documented on Wikipedia.
The fictional high school in fictional Webster Mills, MO is named after Jacques Derrida, the French philosopher known for his theory of deconstructionism. Many of the aphoristic statements which can be read in the questionnaire handed over at the Pontifex Institute meeting, while not direct quotation from Derrida, have a clear relationship with Derrida's works.