The governor of an arid western state owned a vacation home and permitted his son to have a party there. at the end of the night the son failed to properly extinguish a bonfire that he and his friends had built, and within a few hours, wind-blown cinders had spread the fire to the trees east of the lodge. at the same time several miles away, a worker at a lumber mill was making emergency repairs to a pipe running between two mill buildings. he did not notice some of the sparks from his welding torch land in a pile of dried lumber and catch fire, and he failed to check the area after he was finished. by the time the fire was noticed by another employee, it was out of control. the wind blew both fires toward a landowner's hunting lodge. they merged a mile away and shortly thereafter totally consumed the lodge. for political reasons, the landowner did not bring a lawsuit against the governor or his son. he did, however, file a lawsuit against the lumber mill, alleging that its employee's negligence caused the destruction of his lodge. evidence at trial established that either fire alone would have destroyed the lodge as well. can the landowner recover from the lumber mill?