Mike D'Angelo’s review published on Letterboxd:
Got really excited early on when it looked as if this might be a full-bore tale of the uncanny, as Sjöström (whose The Wind is one of my two or three favorite silents) excels at expressionism. And the sequences involving the titular carriage are truly fantastic, in both senses of the word—never imagined I'd see double exposure used so evocatively, especially in the stunning interlude that finds the first coachman collecting the body of a drowned man by driving straight into the ocean. Nested flashback structure is also impressive (especially for 1921), and Sjöström isn't afraid to be thoroughly despicable as the story's lost soul. Ultimately, though, the didactic source material overpowers the artistry. According to Wikipedia, Thy Soul Shall Bear Witness! (now that's a title!) was primarily intended as a primer on how to avoid contracting tuberculosis, which explains the memorable intertitle "All night long she bent over the coat, never giving a thought to the germs and filth she inhaled." The Phantom Carriage puts considerably less emphasis on the dangers of contagion, but it retains Sister Edit the plaster saint, whose beatitude drags the movie down every time it returns to her. Still, decidedly worth seeing, if only for some of the most remarkable F/X work in cinema history.