
Father Merrin (1973)	Pierre Teilhard (1881-1955)
Left: paleontologist-priest, played by Swedish actors Max Sydow (1929-); and later by Stellan Skarsgard (1951-). Right: Pierre Teilhard the French philosopher, Jesuit priest and paleontologist, who notably took part in the discovery of the 500,000-year old Peking man, a corroboration of evolution theory, who attempted throughout his prodigious number of publications to reconcile religion with modern science.

In films, Father Merrin, or Lankester Merrin, played by Swedish actor Max von Sydow, in the 1973 film The Exorcist (9th highest adjusted grossing movie), a film-version adaptation of the 1971, 11-million copy selling book by American writer William Blatty, was based on French philosopher Pierre Teilhard, and his life-long efforts to reconcile religion (good and evil), evolution, consciousness, chemistry, and thermodynamics into one unified theory. [1] A specific referenced explanation remains to be found to detail how exactly and how much Blatty was influenced by Teilard, but, in any event, as filmographer Colleen McDannell points out: [2]

“Blatty has frequently explained that he thought about Jesuit priest-philosopher-paleontologist Pierre Teilhard when creating the character Father Merrin, who besides spending years in China on archaeological digs, taught physics and chemistry at a Jesuit college in Egypt.”

It is said that parts of the plot were themed on Teilhard’s theory of evil (or the existence of Satan) in the world possibly being Lucifer [or matter-energy spirit] working out his [or its] salvation through the process of physical evolution ending in Teilhard’s omega point. This, supposedly, is captured in the use of "psychic energy" and the "unity of minds" or "world mind" (noosphere) theories of Teilhard. [3]

Theory
The following opening quote from the book version of The Exorcist is said to capture the theoretical aspects of Blatty’s mindset: [5]

"Matter is Lucifer crawling itself back to God"

(Matter [is] Lucifer upward groping back to his God)

This means, supposedly, that matter (humans being an evolved incarnation of matter) must work its way through the permutations of entropy, chaos, and generally things that make humanity unhappy in order to know about good and evil. The following is a quote from Blatty (about the novel Legion) which explain his theory: [4]

'In the novel, the coda was needed to put a button on what the novel was all about -- Kinderman's rescue of God's goodness via his theory of "The Angel," which hypothesized that the fall of man was premundane; that before the Big Bang, mankind was a single angelic being who fell from grace and was given his transformation into the material universe as a means of salvation wherein his legion of fragmented personalities would spiritually evolve ("Can there be a moral act without at least the possibility of pain?") back into the original single angelic being, back into himself, a process foreshadowed on the opening page of The Exorcist ("that matter was Lucifer upward groping back to his God").'

References
1. Blatty, William. (1971). The Exorcist. Harper & Row.
2. McDannell, Colleen. (2008). Catholics in the Movies (pg. 209). Oxford University Press.
3. Anon. (1977). “Article”, The Review of the News (pg. 24). Volume 13.
4. Matter is Lucifer crawling itself back to God (2007) – Ask.Metafilter.com.
5. Szumskyj, Benjamin. (2008). American Exorcist: Critical Essays on William Peter Blatty (pg. 34). McFarland.

External links
● Lankester Merrin – Wikipedia.
● The Exorcist – Wikipedia.
● Father Merrin – Imdb.com.