> The horse, raced past the barn, fell But that changes the meaning. Consider a situation where you have two horses. One of them has been raced past the barn;

> The horse, raced past the barn, fell But that changes the meaning. Consider a situation where you have two horses. One of them has been raced past the barn; the other never has. This matters because inside the barn there is an alien artefact emitting radiation that weakens the muscles. But that was yesterday. Today you have sent both horses out for another canter -- and one of them has suffered a fall. Tell me, Igor, which one was it? Did the radiation from the alien artefact cause the trouble? "The horse raced past the barn fell." But the version with the commas is only applicable when (1) you already know which horse is being referred to and (2) the fall happens in racing past the barn or at least as an immediate consequence, it seems to me.