Ahem, pardon me. I was wrong earlier in saying, first, that the stabbing of the dybbuk? is the only physical violence in the movie, and then was wrong again when I thought the car crash was the only other instance of violence. However, I am sticking with my story that the movie is fundamentally (physicists like to say that word) a cartoon. The violence, like the movie, is not to be taken seriously. So of course the Coen brothers call it A Serious Man. An obvious alternate misleading title would be A Serious Movie. However, we can paraphrase good old A. D' Abro (below) and say the obvious is not necessarily credited with any deep significance in moviemaking. It is the veiled.
The other cartoon-like violence in the movie occurs in each of Larry's three dreams. First, in the classroom dream, Sy, the serious man of the movie (according to Nachtner, and also according to Sy himself in this particular dream-scene), bashes Larry into the chalkboard while telling him he made a cuckold of him. Sy doesn't use the word cuckold, however. He uses the f-word, and this is the only time I can think of when an adult utters a profanity, unless you count the Torah hoister muttering "Jesus Christ!" when he almost drops the heavy scroll near the end of Danny's bar mitzvah. (The kids are using profanity all the time.) The physical bashing of Larry by the dybbuk-Sy in the dream contrasts nicely with Sy's warm-huggy-bear approach to taking advantage of Larry when he, Sy, was alive.
The Sex with Mrs. Samsky dream ends with Sy putting boards over Larry like he was burying him alive, saying "Nailing it down, so important." This isn't literal violence but is threatening nevertheless. Mrs. Samsky's cigarette smoke is rather threatening, also, especially when you consider that Larry is, at the end of the movie, called back to the doctor because of something detected in his chest x-rays.
And the shooting, of course, of Uncle Arthur in the Escape to Canada dream. The dream ends with Mitch being told by his dad, both of them in their hunting outfits with rifles, to shoot Larry next ("There's another Jew, son!") and Mitch aims and fires--then the dream ends.
"No Jews were harmed in the making of this motion picture," is the disclaimer after the credit roll at the end of the movie.