dissenting.
My opinion delivered on February 10, 1988 is withdrawn and the following is substituted.
*97The majority opinion is inconsistent with Duncan v. Cessna, 665 S.W.2d 414 (Tex. 1984), comment n of § 402A of the Restatement (Second) of Torts, and denies respondents their right to a trial by jury.
I believe that Keen’s negligence was more than a mere failure to discover or guard against a product defect. Since there is some evidence to support the jury verdict, the court of appeals correctly reduced Keen’s recovery in accordance with the jury’s findings on contributory negligence. I would affirm the judgment of the court of appeals.
In Duncan, this court created a common law scheme of comparative causation for product liability cases in which one defendant is found liable on a theory other than negligence. Realizing the need for a comprehensive system for loss allocation in order to eradicate the confusion, unmanagea-bility and inherent unfairness pervading Texas products law, the court adopted a system which:
will allow comparison of plaintiff’s conduct, whether it is characterized as assumption of risk, misuse, or failure to mitigate or avoid damages, with the conduct or product of a defendant_ Assumption of risk and misuse will no longer be separate defenses, but will be subsumed under the more familiar notion of contributory negligence.
Id. at 428.
In addition, Duncan reaffirmed our prior adherence to that part of comment n of § 402A of the Restatement (Second) of Torts which provides that the contributory negligence of the plaintiff in failing to discover a defect, or to guard against the possibility of its existence, is not a defense. Id. at 432; Shamrock Fuel & Oil Sales Co. v. Tunks, 416 S.W.2d 779 (Tex.1967); McKisson v. Sales Affiliates, Inc., 416 S.W.2d 787 (Tex.1967). Strong public policy reasons dictate that we continue to reject suggestions that we abandon comment n altogether in fashioning comparative causation schemes. As one court stated, “to penalize a consumer for failing to discover defects or to guard against them places a burden on consumers which strict liability was intended to remove.” Star Furniture Co. v. Pulaski Furniture Co., 297 S.E.2d 854, 862-63 (W.Va.1981). Thus, I advocate the continued adherence to comment n. However, it is unfair for the majority to ignore the jury finding that Keen’s conduct fell below that of a person using ordinary care. This is a violation of respondent’s rights to trial by jury guaranteed by article 1, section 15 and article 5, section 10 of the Texas Constitution and the seventh amendment to the U.S. Constitution.
In the instant case, the jury found in Issue 7 that “Keen moved his hostling tractor beside the trailer-chassis combination when it would not have appeared to a person using ordinary care that such movement could be made with safety.” The jury also found that Keen’s negligence was a proximate cause of the occurrence and that Keen’s conduct contributed fifty percent to his injuries. The jury was instructed to “not consider any conduct of the plaintiff which amounts only to a failure to discover or guard against a product defect, if any.” A jury is presumed to have followed the trial court’s instructions. Turner, Collie & Braden, Inc. v. Brookhollow, Inc., 642 S.W.2d 160, 167 (Tex.1982). Thus, we have a situation where a jury has found Keen to be negligent for reasons other than his mere failure to discover a product defect.
The majority concedes two crucial pieces of undisputed testimony: Keen knew (1) it was very common for trailers to lean, and (2) it was a recognized safety rule not to pull alongside a trailer in motion or in the process of being set down because of the risk that it could fall and cause injury. In violation of this safety rule, Keen pulled his hostler alongside Moody’s trailer while Moody was disengaging. Keen’s co-worker, Moody, also testified that it was a recognized practice to park behind trailers which were being set down rather than alongside them.
A review of two prior Texas cases illustrates the application of the “failure to discover” rule. In Shamrock Fuel & Oil *98Sales Co. v. Tunks, 416 S.W.2d 779 (Tex. 1967), the jury found a plaintiff contribu-torily negligent in causing an explosion by directing his brother to pour kerosene adulterated with gasoline upon a smoldering stick. This court set aside that finding because it embraced a mere failure to discover a defect or guard against the possibility of its existence. Shamrock, 416 S.W. 2d at 785. In McKisson v. Sales Affiliates, Inc., 416 S.W.2d 787 (Tex.1967), the jury found that a reasonably prudent beauty operator in the exercise of ordinary care would have known that the defendant's wave lotion should not be applied to bleached hair. Determining that Mrs. McKisson was at most negligent in not discovering that the product was unsuitable for bleached hair, this court refused to allow such conduct as a defense. McKisson, 416 S.W.2d at 793.
In neither case do we have evidence that the injured plaintiff knew that he or she was taking a risk by engaging in such conduct. Rather, the evidence showed that a reasonably prudent person should have known that the conduct might cause harm. A consumer’s “unobservant, inattentive, ignorant, or awkward failure to discover or guard against a defect should not be compared as a damage-reducing factor.” Coney v. J.L.G. Industries, Inc., 97 Ill.2d 104, 73 Ill.Dec. 337, 454 N.E.2d 197, 204 (1983). In Shamrock, the plaintiff might have avoided injury had he tested the kerosene or discovered its dangerously low flash point. Shamrock, 416 S.W.2d at 784. The fact remains, however, that the plaintiff’s conduct amounted to no more than a failure to acquire knowledge of a danger which a prudent person would have obtained. In McKisson, the plaintiff used a hair lotion which contained a label “for normal or resistant hair....” Although she knew her hair was bleached, Mrs. McKisson nonetheless testified she considered her hair to be normal, not resistant. Further, she testified that although she knew a different formula was ordinarily used for bleached hair, she believed that most preparations which were unsuitable for bleached hair contained warnings to that effect. McKisson, 416 S.W.2d at 791. Once again, the plaintiff should have known that what she was doing was dangerous, but she did not. No evidence was presented in either case of a pre-accident warning or rule not to use the product in a certain manner.
In the instant case, Keen himself testified he knew about a safety rule not to pull alongside a trailer because of the risk it could fall and cause injury. In disregard of this safety rule, Keen pulled alongside the trailer and was injured. From this evidence, the jury could have found that Keen moved his hostling tractor alongside the trailer-chassis combination when an ordinarily prudent person in the same circumstances would not have done so. It matters not that the cause of the accident was due to a defective sandshoe rather than an improperly balanced load, a windstorm, or some other type of occurrence which caused the trailer to fall. The issue is not what caused the trailer to fall, but what caused the injury to Keen.
A plaintiff’s recovery should not be increased or diminished by reason of the nature of the defect. Rather, the plaintiff’s recovery should be calculated by comparing the injured plaintiff’s knowledge of a potential risk versus the liability of the defendant for its defective product. Thus, while the accident was caused by a defective sandshoe, the injury was caused by a product defect and a contributorily negligent plaintiff who knew better than to approach the trailer in the manner in which he did. As we stated in Duncan:
Comparative causation is especially appropriate in crashworthiness cases where the product defect causes or enhances injuries but does not cause the accident. The conduct which actually causes the accident, on the other hand, would not cause the same degree of harm if there were no product defect. Rather, it is a combination of factors that causes plaintiff’s injuries. The jury is asked to apportion responsibility between all whose action or products combined to cause the entirety of the plaintiff's injuries, (emphasis added)
*99Duncan, 665 S.W.2d at 428. We also stated:
The trier of fact is to compare the harm caused by the defective product with the harm caused by ... the plaintiff.
Id. at 427. Moreover, the comparative apportionment issue is phrased in terms of the percentage of plaintiff’s injuñes. Id. at 427 n. 8.1 Because Keen’s own undisputed testimony reveals that he knew of the risk he was taking by pulling his hostler beside the trailer, Shamrock and McKisson are inapposite.
Comment n of § 402A of the Bestatement (Second) of Torts states:
Contributory negligence of the plaintiff is not a defense when such negligence consists merely in a failure to discover the defect in the product, or to guard against the possibility of its existence. On the other hand the form of contributory negligence which consists in voluntarily and unreasonably proceeding to encounter a known danger, and commonly passes under the name of assumption of risk, is a defense under this Section as in other cases of strict liability. If the user or consumer discovers the defect and is aware of the danger, and nevertheless proceeds unreasonably to make use of the product and is injured by it, he is barred from recovery, (emphasis added).
The court in Duncan focused on the question of:
“whether a plaintiff’s contributory negligence is a defense in strict products liability actions when that negligence does not rise to the level of assumed risk or unforeseeable product misuse, but is more than a mere failure to discover a product defect....”
Duncan, 665 S.W.2d at 422 (emphasis added). Thus, it is clear that our court in Duncan recognized a middle category of plaintiff’s conduct that is neither assumed risk nor a mere failure to guard against a product defect.
In Duncan, the pilot of the airplane was negligent in the manner in which he flew the plane, but he had no knowledge of the defect in the plane’s construction. Yet the court plainly suggested that the pilot’s contributory negligence would have been a comparative defense. Is it the majority’s intent, without taking any notice of this matter, to reverse Duncan? Henceforth, will we require that an injured plaintiff have knowledge of the defect before his own negligent conduct will constitute a comparative defense?
Professor William Powers, Jr., in an ami-cus brief filed on motion for rehearing, presents the following illustration regarding Duncan and comment n. There are three categories of contributory negligence recognized in Duncan.
Category I Category II Category III
Plaintiff is negligent only because he fails to discover or guard against the defect. Plaintiff does not know of a defect, but is negligent without regard to the defect. Plaintiff is actually aware of the defect (assumption of risk).
Keen’s conduct falls into the second category. By failing to recognize this category of conduct, the majority has ignored Duncan and comment n, and has created uncertainty and confusion about the continued validity of the court’s writing in Duncan. Furthermore, by disregarding the jury findings, the court has denied respondents their right to a trial by jury.
*100I would hold that the jury’s finding of contributory negligence has some evidence to support it. Since the majority incorrectly determines that Keen’s negligence is no defense to this products liability action, I dissent.
. In framing this issue in terms of “injury,” we specifically noted analogous special issues from maritime seaworthiness cases. Duncan, 665 S.W.2d at 427 n. 8 (citing Daly v. General Motors Corp., 20 Cal.3d 725, 144 Cal.Rptr. 380, 575 P.2d 1162 (1978)). Both in the area of federal maritime law, and in California’s apportionment scheme for strict products liability, the jury is asked to consider the extent to which a plaintiffs own negligence contributes to his injuries. See Daly, 575 P.2d at 1168-70.