What is the test for determining whether a product is defective or defective?

[20 Cal.3d 753] A consideration of the instructions likely to be given to the jury under the majority's holding will reveal the merit and substantiality of the objections to the majority's views. Thus, a jury may, or may not, receive an instruction defining a "defect" in a product or a "defective" product. (See Barker v. Lull Engineering Co. (1978) 20 Cal.3d 413, 143 Cal.Rptr. 225, 573 P.2d 443.) The definition of negligence, usually given to a jury, is found in BAJI Instruction No. 3.10. ¹ We can assume that, in substance, the jury will be told that if it finds that defendant's product was defective in manufacture or design and that such defective product was a proximate cause of plaintiff's injuries, and that if it also finds that plaintiff was negligent and that such negligence was also a proximate cause of plaintiff's injuries, the two factors are to be considered as constituting 100 percent of fault (assuming there are no other proximate causes) for plaintiff's injuries. The jury will then be told to determine what percentage each of these factors contributes to reach the 100 percent total.