The Exorcist movie review & film summary (1973) | Roger Ebert

https://www.rogerebert.com/reviews/the-exorcist-1973#:~:text=We%20don't%20necessarily%20believe,small%20measure%20of%20dogged%20hope. 

[ The story is well-known; it’s adapted, more or less faithfully, by William Peter Blatty from his own bestseller. Many of the technical and theological details in his book are accurate. Most accurate of all is the reluctance of his Jesuit hero, Father Karras, to encourage the ritual of exorcism: “To do that,” he says, “I’d have to send the girl back to the sixteenth century.” Modern medicine has replaced devils with paranoia and schizophrenia, he explains. Medicine may have, but the movie hasn’t. The last chapter of the novel never totally explained in detail the final events in the tortured girl’s bedroom, but the movie’s special effects in the closing scenes leave little doubt that an actual evil spirit was in that room, and that it transferred bodies. Is this fair? I guess so; in fiction the artist has poetic license. " ]