dissenting.
Claimant fell and was injured at work. All the medical experts agree that there is no objective medical evidence of the cause of his fall. In the words of Dr. Reinhart, a witness for employer, “I think it will be impossible to define a clear etiology for this event.”
Phil A. Livesley Co. v. Russ, 296 Or 25, 30, 672 P2d 337 (1983), holds that, if a worker’s fall is unexplained, it is *223compensable, but if it resulted from idiopathic causes, it is not. The burden of “persuasively” eliminating idiopathic causes is on the claimant. 296 Or at 30. The medical evidence in this case is that many possible idiopathic causes of a fall can never be eliminated. Therefore, if “persuasively” eliminating idiopathic causes requires that a claimant must prove that none could exist, Livesley is meaningless.
I would hold that a claimant persuasively eliminates idiopathic causes if he eliminates the most probable idiopathic causes of an event, and the remaining possibilities are not capable of being proven or disproven. The majority finds that “the most plausible explanation” of the fall is that claimant fainted. The majority ignores the one clear piece of medical evidence: no one knows why claimant fell. Unfortunately, it then decides the case by making a guess. If that method is to be used to analyze these kinds of cases, it could be that no injury could ever be from “unknown” causes.
The neurologist’s explanation of the evidence is most persuasive to me:
“There is no way of knowing if there was some physiological cause of a lapse of conciousness * * *. In other words, since there is no proof to the contrary, a diagnosis of cerebral concussion, occipital laceration and cervical strain superimposed on cervical spondylosis (etiology unknown) would be a more appropriate diagnosis.”
Claimant eliminated discernable heart and neurological problems as the cause. Employer’s witness could not even identify the most probable among other possible, unascertainable causes. The cause of claimant’s fall was unknown. He should receive benefits.