dissenting:
¶ 31 I respectfully dissent. The majority concedes that “the facts of the case must merit the proposed instruction.” I do not believe the facts of this case required the court to give the instruction plaintiff Robinson requested. Although Robinson presented evidence that most of his injuries were attributable to the 1995 accident, he failed to present evidence that causation and damages could not be apportioned between the 1995 accident and the 1991 accident.
¶32 The majority relies on Tingey v. Christensen, 987 P.2d 588 (Utah 1999), which in turn relied on Newbury v. Vogel, 151 Colo. 520, 379 P.2d 811, 813 (1963) (en banc), and its progeny. Newbury held that “where a pre-existing ... condition exists, and ... no apportionment of the disability between that caused by the pre-existing condition and that caused by [a later] trauma can be made ... the defendant! ] whose act of negligence was the cause of the trauma! ] is responsible for the entire damage.” 379 P.2d at 813. In Tingey, we stated that the Newbury rule, and its attendant jury instruction, was supported by several oft-stated principles:
[F]irst, a tortfeasor takes a tort victim as he or she finds the victim; second, a tort-feasor should bear the’ burden of uncertainty in the amount of a tort victim’s damages; and third, once the fact of damage is established, “a defendant should not escape liability, because the amount of damage cannot be proved with precision.”
Tingey, 987 P.2d at 592 (quoting Winsness v. M.J. Conoco Distrib., Inc., 593 P.2d 1303, 1306 (Utah 1979)) (other citations omitted).
¶ 33 Regardless of the general validity of these propositions, I believe Tingey (as well as the majority opinion in the instant case) inadequately elucidated all of the pertinent legal principles governing the appropriateness of granting a plaintiffs request for a Newbury instruction. The chief pitfall of presenting a jury with a Newbury instruction is that it “effectively places the burden on ... defendants to show what portion of the injury predated the accident, as ... failure to do so would allow recovery for the preexisting injury as well as that caused by the defendants.” LaMoureaux v. Totem Ocean Trailer Express, Inc., 632 P.2d 539, 543 (Alaska 1981).
¶ 34 In LaMoureaux, the Alaska Supreme Court addressed the dilemma of proof presented in preexisting condition cases by comparing those cases with the scenario presented in Summers v. Tice, 33 Cal.2d 80, 199 P.2d 1, 2 (1948) (en banc), wherein two negligent defendants fired birdshot in the plaintiffs direction. In Summers, the defendants bore the burden of proof with respect to causation because the plaintiff would otherwise “recover nothing unless he was able to fix the blame on one of the two wrongdoers.” *978LaMoureaux, 632 P.2d at 544. The LaM-oureaux court observed that causation in preexisting condition cases presents a similar problem because “it is often difficult to determine how much of a plaintiffs injury is due to the preexisting condition and how much to the aggravation caused by the defendant.” Id. Thus, although “a decision to place the entire liability [for both the current injury and the preexisting condition] on the defendant is an extreme measure” and should be done only when there is no reasonable alternative, id. at 545 (citing W. Prosser, Law of Torts § 52, at 314 (4th ed.1972)), there are circumstances when it may be more just to do so than to leave an innocent plaintiff with no recovery whatsoever simply because it is difficult or impossible to prove the appropriate degree of apportionment.
¶ 35 Hence, LaMoureaux acknowledged that, in circumstances where difficulty of proof exists, the plaintiff may be justifiably “reliev[ed] of proving with great exactitude the amount of aggravation,” id. at 544; but LaMoureaux nevertheless rejected a wholesale shifting in the burdens of proof traditionally borne by plaintiffs. In this regard, the Alaska court noted that there is one critical distinction between the preexisting condition cases and the multiple defendant scenario presented in Summers:
Where two tortfeasors are involved, they presumably can furnish evidence as to their degree of contribution to plaintiffs injury. But, if the plaintiff is suffering from a preexisting injury, he or she is in the best position to furnish information on the degree to which that injury was aggravated by the defendant’s acts.
Id. at 545. Thus, LaMoureaux held that a Newbury instruction should be given only after the plaintiff has “come forward with evidence as to an earlier injury” but medical experts are still unable to apportion the amount of aggravation. Id.
¶ 36 I agree with LaMoureaux and would adopt its reasoning on the basis of its persuasive discussion of the policies that ought to govern jury instructions for apportionment of causation and damages in preexisting injury cases. I would hold that plaintiffs are not entitled to a Newbury instruction unless they have presented competent testimony asserting the impossibility of allocating causation and damages for injury as between the current defendants and preexisting conditions. For example, where a plaintiff presents appropriate evidence of the nature and extent of his or her preexisting conditions, accompanied by expert testimony that no apportionment of causation and damage is possible, the burden properly shifts to the defendant to rebut the plaintiffs testimony and demonstrate that apportionment is in fact possible. In such cases, the plaintiff will have properly met his or her burden regarding the impossibility of apportionment and is entitled to a Newbury instruction. The jury can then weigh the evidence presented by each side and — on the basis of competent evidence, not upon the plaintiffs failure to come forward with all the necessary information pertaining to his or her preexisting condition — determine whether apportionment is possible and, if so, what apportionment should be made. Otherwise, the Newbury instruction effects an impermissible shifting in the burden of proof without a justifiable evidentiary basis for that shift.
¶ 37 In view of these principles, I do not believe the facts of this case justified a New-bury instruction. Although there was conflict in the testimony as to the degree of Robinson’s injuries that was attributable to the 1995 accident, as distinguished from the 1991 accident, Robinson did not show that it was impossible to apportion causation and damages. Moreover, to the extent Robinson’s expert, Dr. Horne, was unable to apportion between the 1991 accident and the 1995 accident, it was due to a lack of information, not a professional determination, that no such apportionment could be made.1 Although Dr. Horne testified he was a member of the Labor Commission and had extensive experience in assessing impairment ratings, he had not examined Robinson extensively enough prior to 1995 to testify as to what level of impairment, or lack thereof, Robinson had suffered as a result of the 1991 *979accident. Thus, in this case, Robinson, who was in the best position to provide competent medical testimony as to the possibility of apportioning causation and damages between his two injuries, failed to meet his burden on that issue.
¶38 By asserting that the facts of this ease justified a Newbury instruction, the majority opinion misconstrues the fundamental principles governing the proper treatment of apportionment problems. A Newbury instruction should not be mandated whenever there is any conflicting evidence regarding the degree of apportionment. Rather, a Newbury instruction should be mandated only when there is a specific dispute, supported by appropriate evidence, regarding the possibility of apportionment. Consequently, the jury was not properly presented with a question as to impossibility of apportionment and a Newbury instruction was not merited. I therefore dissent.
. Robinson visited Dr. Horae on two occasions in 1993, almost two years after the accident that had caused or contributed to his preexisting conditions.