I dissent.
In Taylor v. Centennial Bowl, Inc. (1966) 65 Cal.2d 114 [52 Cal.Rptr. 561, 416 P.2d 793] (hereafter Taylor), we held that, under the common law of California, “the proprietor of a business establishment” owes a “general duty” to his “business invitees” (id. at p. 121), including a specific duty to “exercise reasonable care for their safety” (ibid.) against, among other things, criminal conduct by third persons (id. at p. 124).
It follows that, under our common law, a business proprietor may or may not be under a duty to accede to the demands of a robber when his customers are present. Perhaps more correctly, he may or may not breach his duty to exercise reasonable care for their safety by refusing. Each case depends on its own facts. To be sure, in many if not most, as law enforcement authorities counsel, he should yield. But, in some perhaps, he need not.
Today, the majority announce a harsh and unjust rule that a business proprietor is never under a duty to accede to the demands of a robber when his customers are present, that he never breaches his duty to exercise reasonable care for their safety by refusing. They conclude, underneath their words, that a business proprietor is immune as a matter of law insofar as his customers find themselves in the presence of a robber. That is to say, a business proprietor is never required to subordinate any of his own property interests—no matter how insignificant the object and no matter how slightly it is jeopardized—to his customers’ safety—no matter how many they are and no matter how gravely they are threatened. To expose such a conclusion is to prove its unsoundness.
*831In support of their harsh and unjust rule, the majority invoke “public policy,” but to no avail. Whether the immunity they grant to business proprietors will indeed deter robbers, as they assert by ipse dixit without empirical support, depends on whether street criminals are in fact rational decisionmakers—a proposition that they themselves effectively reject when they imply that “[r]obbers are unpredictable” (maj. opn., ante, at p. 829).
In support of their harsh and unjust rule, the majority also invoke article I, section 1 of the California Constitution and section 50 of the Civil Code, also to no avail. Section 50 states, in substance, that it is a “personal right[]” (Civ. Code, § 43) to use “[a]ny necessary force ... to protect” one’s “property” “from wrongful injury” (id,., § 50). But section 43 of the same code makes plain that such a “personal right[] ” is not absolute: rather, it is “subject to the qualifications and restrictions provided by law . . . .” (Id., § 43.) One such “qualification” or “restriction” is found in Taylor's common law rule that a business proprietor owes a duty to exercise reasonable care for the safety of his customers against criminal conduct by third persons. For its part, article I, section 1 declares: “All people are by nature free and independent and have inalienable rights. Among these are enjoying and defending life and liberty, acquiring, possessing, and protecting property, and pursuing and obtaining safety, happiness, and privacy.” (Cal. Const., art. I, § 1.) “[I]nalienable rights” are not ipso facto absolute rights. That is true of all the enumerated rights—including those relating to property (e.g., Max Factor & Co. v. Kunsman (1936) 5 Cal.2d 446, 458 [55 P.2d 177], affd. sub nom. Pep Boys v. Pyroil Sales Co. (1936) 299 U.S. 198 [81 L.Ed. 122, 57 S.Ct. 147]).
For the reasons stated above, I would affirm the judgment of the Court of Appeal.
KENNARD, J., Dissenting.In this case, a patron was taken hostage during a restaurant robbery. Holding a gun to the patron’s back, the robber demanded that the cashier open the cash register. The cashier refused, falsely stating that she did not have a key to the register. The robber repeated his demand and threatened to kill the patron. The cashier then complied and gave the robber the money; the robber released the patron and fled. The patron, claiming that she suffered injury from this ordeal, has now sued the restaurant for negligence.
Negligence law holds one liable for failing to use reasonable care to avoid harm to others only in those cases where one has a duty to use reasonable care. To determine liability, it is necessary to distinguish between the *832separate questions of whether a duty exists and whether a duty that exists has been breached by the failure to use the care that a reasonable person would have used under the circumstances. Whether a defendant has a duty to use reasonable care to avoid harm to the plaintiff is decided as a matter of law by the court. If the court finds that a duty exists, the next question is whether the defendant used reasonable care. It is generally the jury, as trier of fact, that decides whether the defendant used the care that a reasonable person would use under the circumstances to avoid harm to the plaintiff.
Here, the majority and I agree that the restaurant had a duty to take reasonable steps to protect its patrons from foreseeable assault by third parties on the premises. This court has long recognized such a duty. (Taylor v. Centennial Bowl, Inc. (1966) 65 Cal.2d 114 [52 Cal.Rptr. 561, 416 P.2d 793].) Given this duty, the question of whether the restaurant breached this duty and failed to use due care when its cashier initially refused to comply with the robber’s demands is a question for the jury. Because the restaurant has not shown that reasonable minds could only decide this issue in its favor, the trial court and the Court of Appeal correctly concluded that the restaurant was not entitled to summary judgment on this issue.
The majority reaches a contrary result; it errs, however, by mistakenly framing the issue before us as an issue of duty to be decided by the court as a matter of law rather than as an issue of reasonable care for the jury. For the majority, the issue is whether a business proprietor always (or never) has a “duty” to comply with the demands of a robber who threatens a customer with harm; the majority concludes that a business proprietor need never protect its customers by doing so.
The issue before us, however, is properly a question of whether defendant’s cashier, in initially refusing to comply with the robber’s demand, breached the reasonable person standard of care, not whether defendant was under a “duty” to follow a prescribed course of conduct. By framing the issue as a question of duty, the majority usurps the jury’s historic function in a negligence case to determine the reasonableness of defendant’s conduct under the surrounding circumstances.
I
Plaintiff Kathy Brown was a customer at a restaurant, owned by Kentucky Fried Chicken of California, Inc. (KFC), when an armed robber entered, put a gun to Brown’s back, and demanded money from the restaurant and her. Brown complied; the store cashier did not, instead falsely telling the robber that she would have to get a key for the cash register from the back of the *833restaurant. The robber became agitated and angry, shoved his gun in Brown’s back, and told the cashier he would shoot Brown unless the cashier “quit playing games” and opened the register immediately. Brown screamed that the cashier should open the register. The cashier then opened the register and gave the money to the robber, who fled.
Brown sued KFC, seeking damages for personal injury. Brown alleged that KFC’s cashier acted negligently by initially refusing to comply with the robber’s demands and that KFC had failed to provide proper security and to adequately train its employees. KFC moved for summary judgment, arguing that it had no duty to protect Brown against criminal acts by third parties in the absence of prior similar incidents or to comply with the requests of criminals, and that even if a duty was owed to Brown, KFC had not breached it.
The trial court denied KFC’s motion for summary judgment. KFC petitioned the Court of Appeal for a writ of mandate to compel the trial court to grant summary judgment for it. The Court of Appeal denied the petition in a written opinion.
II
A finding of negligence depends on two determinations. The first determination, a question of law for the court, is this: Does the defendant have a duty to protect the plaintiff from a particular type of harm? (See Ann M. v. Pacific Plaza Shopping Center (1993) 6 Cal.4th 666, 673 [25 Cal.Rptr.2d 137, 863 P.2d 207].) The second determination, necessary only if a duty is found to exist, is this: Did the defendant’s conduct satisfy the standard of care that the duty imposes? (See ibid.; Ramirez v. Plough, Inc. (1993) 6 Cal.4th 539, 546 [25 Cal.Rptr.2d 97, 863 P.2d 167, 27 A.L.R.5th 899].) (Ordinarily, the standard is to act as a reasonable person would under similar circumstances. See Ramirez v. Plough, Inc., supra, 6 Cal.4th 539, 546.) This is generally a question for the jury as trier of fact. (Ibid.)1
With respect to the question of duty, this court in Taylor v. Centennial Bowl, Inc., supra, 65 Cal.2d 114, recognized a business proprietor’s duty to use reasonable care to protect customers who visit its premises from assault by third parties. Taylor held that “the duty owed by the proprietor of a business establishment to business invitees” includes the duty to “exercise *834reasonable care for their safety,” and specifically “the duty to take affirmative action to control the wrongful acts of third persons which threaten invitees where the occupant has reasonable cause to anticipate such acts and the probability of injury resulting therefrom.” (Taylor v. Centennial Bowl, Inc., supra, 65 Cal.2d 114, 121; accord, Ann M. v. Pacific Plaza Shopping Center, supra, 6 Cal.4th 666, 674; Isaacs v. Huntington Memorial Hospital (1985) 38 Cal.3d 112, 123 [211 Cal.Rptr. 356, 695 P.2d 653]; Peterson v. San Francisco Community College Dist. (1984) 36 Cal.3d 799, 806-807 [205 Cal.Rptr. 842, 685 P.2d 1193].) The majority acknowledges the continuing validity of Taylor, as the majority also acknowledges, section 344 of the Restatement Second of Torts, which the Taylor court cited with approval, similarly recognizes that business proprietors have a duty to “exercise reasonable care ... [f] ... to protect [their patrons] against” the “harmful acts of third persons.”
“[T]he duty to take affirmative action to control the wrongful acts of third persons which threaten invitees” (Taylor v. Centennial Bowl, Inc., supra, 65 Cal.2d 114,121) does not end once an attack on a patron is in progress. This duty obligated KFC not only to take reasonable care to protect against such wrongful acts by third persons but also, if such acts occurred nonetheless, to take reasonable care to avoid increasing the risk of injury to its patrons from those acts. (See Trujillo v. G.A. Enterprises, Inc. (1995) 36 Cal.App.4th 1105, 1109 [43 Cal.Rptr.2d 36]; Marois v. Royal Investigation & Patrol, Inc. (1984) 162 Cal.App.3d 193, 199, 201 [208 Cal.Rptr. 384]; Rest.2d Torts, § 344, com. f, p. 225 [proprietor’s duty to use reasonable care to protect patrons from acts of third persons exists when proprietor “knows or has reason to know that the acts of the third person are occurring”].) Other courts have similarly required business proprietors to use reasonable care to avoid increasing the risk to patrons during a robbery. (Helms v. Church’s Fried Chicken, Inc. (1986) 81 N.C.App. 427 [344 S.E.2d 349, 351] [applying “the general principle that a defendant owes a duty not to increase foreseeable risk of harm to another” to a business proprietor’s conduct during a robbery]; Kelly v. Kroger Company (10th Cir. 1973) 484 F.2d 1362, 1364; Helms v. Harris (Tex.Civ.App. 1955) 281 S.W.2d 770, 772 [“when acts in self-defense or in defense of one’s property are committed under circumstances where the actor should realize that such acts create an unreasonable risk of causing harm to innocent third parties . . . such third parties may subject the actor to liability”]; see Annot., Liability of Storekeeper for Death of or Injury to Customer in Course of Robbery (1976) 72 A.L.R.3d 1269, 1273 [“if a proprietor acts, or fails to act, against an armed robber when he should reasonably foresee that his action, or inaction, could proximately result in injury to the customer, then the proprietor would presumably be liable for such injuries”].)
*835Given the existence of KFC’s duty to use reasonable care to prevent harm to Brown during the robbery, whether it and its employees met the standard and acted reasonably is a question for the jury, unless reasonable minds could not differ on the question. (Ramirez v. Plough, Inc., supra, 6 Cal.4th 539, 546.) The answer to that question depends on the circumstances of the particular case, and cannot be determined as a rule of law that, regardless of the surrounding circumstances, applies to all defendants presented with a similar risk of harm to another. “Because application of [the reasonable person standard] is inherently situational, the amount of care deemed reasonable in any particular case will vary, while at the same time the standard of conduct itself remains constant, i.e., due care commensurate with the risk posed by the conduct taking into consideration all relevant circumstances.” (Flowers v, Torrance Memorial Hospital Medical Center (1994) 8 Cal.4th 992, 997 [35 Cal.Rptr.2d 685, 884 P.2d 142].)
Accordingly, the reasonable person standard of care may require less care during a robbery, or other criminal event, than it does under calmer and more composed circumstances. Robberies are stressful and unpredictable encounters, frequently fast paced, in which those being robbed are forced to decide and act, often instantaneously, upon necessarily incomplete information about the situation that confronts them. Under such circumstances, the scope of what is reasonable is necessarily wide, and often there may be a number of alternative courses of action that, given the circumstances, will be equally reasonable.
The standard California jury instructions on negligence include an instruction recognizing that a person confronting a sudden danger “is not expected nor required to use the same judgment and prudence that is required in the exercise of ordinary care in calmer and more deliberate moments.” (BAJI No. 4.40 (8th ed. 1994).) The instruction explains: “[His] [Her] duty is to exercise the care that an ordinarily prudent person would exercise in the same situation. If at that moment [he] [she] does what appears to [him] [her] to be the best thing to do, and if [his] [her] choice and manner of action are the same as might have been followed by any ordinarily prudent person under the same conditions, [he] [she] does all the law requires of [him] [her]. This is true even though in the light of after-events, it should appear that a different course would have been better and safer.” (Ibid.)
The Restatement Second of Torts similarly recognizes that actions may be reasonable in an emergency that might be unreasonable under calmer circumstances that would permit the actor to gather more information and analyze it deliberately and reflectively. (Rest.2d Torts, § 296 [“In determining whether conduct is negligent toward another, the fact that the actor is *836confronted with a sudden emergency which requires rapid decision is a factor in determining the reasonable character of his choice of action.”]; accord, Helms v. Church’s Fried Chicken, Inc., supra, 344 S.E.2d 349, 352; Prosser & Keeton on Torts (5th ed. 1984) § 33, pp. 196-197; Annot., Liability of Storekeeper for Death of or Injury to Customer in Course of Robbery, supra, 72 A.L.R.3d 1269, 1274 [“the occurrence of an armed robbery puts all persons involved under a considerable state of stress, and in determining the standard of care owed by á proprietor toward his customers during an armed robbery of the premises, the so-called ‘sudden emergency rule’ should thus be considered, as it takes into account, in establishing the standard of care, the stress to which the proprietor, as well as other persons on the premises, are being subjected” (fn. omitted)].)
The “inherently situational” reasonable person standard of conduct thus gives business proprietors a wide latitude of discretion in responding to robberies, while nonetheless allowing for liability in those few cases where the proprietor acts unreasonably and causes harm to a customer. The standard of conduct does not require extraordinary heroics or superhuman reactions. In addition, a plaintiff must satisfy the requirement of causation by proving that the proprietor’s conduct, not just that of the robber, was a legal cause of the injury.
In this case, KFC moved for summary judgment on two grounds: (1) It “did not owe plaintiff [either] a duty to protect her from criminal conduct of third persons where there was no knowledge of or occurrence of prior similar criminal acts on the premises” or a duty to comply with the robber’s demands; and (2) even if a duty existed, KFC did not breach that duty. The duty of care that this court recognized in Taylor v. Centennial Bowl, Inc., supra, 65 Cal.2d 114, 121, disposes of the first ground. Once the robbery was in progress the existence of “wrongful acts of third persons” (ibid.) was a certainty and KFC had a duty not to unreasonably increase the risk of harm to Brown. As to the second ground, to prevail on summary judgment, KFC must establish that rational jurors could reach no other conclusion than that KFC and its employees used reasonable care to protect KFC’s patron, Brown. (See Ramirez v. Plough, Inc., supra, 6 Cal.4th 539, 546; Code Civ. Proc., § 437c.)
KFC has not done so. The only evidence that KFC submitted in support of its summary judgment motion was the account of the robbery given by Brown at her deposition and a declaration by a KFC employee stating there had been no previous robberies at the restaurant. This evidence does not carry KFC’s burden of demonstrating that no rational juror could conclude *837that KFC’s cashier acted unreasonably in initially refusing the robber’s demand and attempting to deceive him by telling him falsely that she could not open the cash register. (See Trujillo v. G.A. Enterprises, Inc., supra, 36 Cal.App.4th 1105, 1108-1109 [whether security guard took reasonable steps to protect patron of fast-food restaurant during assault could not be resolved on summary judgment]; Marois v. Royal Investigation & Patrol, Inc., supra, 162 Cal.App.3d 193, 202 [same; “Where an individual is being physically assaulted, or where another individual is approached by a bat-wielding assailant, it requires no mastery of metaphysical philosophy or economic risk analysis to appreciate the strong possibility of serious injury. The only question in this case is whether the security guards responded reasonably to this clearly foreseeable risk.”].)
Ill
The majority takes a different approach. Instead of recognizing that the reasonableness of the cashier’s conduct presents a jury question of whether the standard of care was breached, the majority reformulates it as a question of duty for the court: Does “the law impose[] a duty to comply with a robber’s demands”? (Maj. opn., ante, at p. 824.)
In doing so, the majority confuses the legal question (for the court) of whether KFC had a duty to protect patron Brown from harm with the question (for the jury) of whether KFC has complied with the standard of conduct imposed by that duty by taking reasonable care not to increase the risk of harm to Brown. By confusing the separate questions of whether a duty exists and whether the standard of care has been breached, the majority makes the unspoken and erroneous assumption that the only alternatives are either to require business proprietors to comply with a robber’s demands in every case or in no case.
The focus of the duty analysis should not be on the details of a defendant’s conduct. The pertinent inquiry is whether a defendant must take steps to avoid causing a given type of harm to the victim. (Coffee v. McDonnell-Douglas Corp. (1972) 8 Cal.3d 551, 558-559 [105 Cal.Rptr. 358, 503 P.2d 1366].) What steps a defendant must take to avoid the harm is a question of whether the defendant has met the standard of care by acting reasonably under the circumstances; also, it is a question that arises only after a duty has been found to exist. (Id. at pp. 558-560.)
Once the majority concludes as it does that KFC and its employees owed patron Brown a duty to take reasonable steps to protect her while she was in the restaurant from the foreseeable criminal acts of others, the question *838whether KFC’s cashier should have complied with the robber’s demands immediately rather than initially refusing to do so is a question of whether the cashier acted reasonably under the circumstances and thereby satisfied the standard of care. This, as I indicated earlier, is a question for the jury, not a question of law for the court: “Once the court has formulated the standard [of care], its application to the facts of the case is a task for the trier of fact if reasonable minds might differ as to whether the defendant’s conduct has conformed to the standard.” (Ramirez v. Plough, Inc., supra, 6 Cal.4th 539, 546; see also Pool v. City of Oakland (1986) 42 Cal.3d 1051, 1061 [232 Cal.Rptr. 528, 728 P.2d 1163] [“the trier of fact determines whether a defendant’s conduct satisfies the applicable standard of care”]; Coffee v. McDonnell-Douglas Corp., supra, 8 Cal.3d 551, 558-560; Weiner, The Civil Jury Trial and the Law-Fact Distinction (1966) 54 Cal.L.Rev. 1867, 1876-1882.) The majority errs in transforming this question into an issue of duty to be answered by the court.2
*839It is always possible to recast any question of whether the standard of care has been breached as a question of “duty,” as the majority does here.3 Thus, instead of asking whether an automobile driver who failed to stop in time used the care of a reasonable driver under like circumstances, we could ask whether the driver had a “duty” to begin braking sooner; instead of asking whether a doctor treated a feverish patient with the care of a reasonable physician we could ask whether the doctor had a “duty” to administer penicillin. If a court does so, however, it abandons the flexibility inherent in the application of the reasonable person standard and instead dictates a rigid, inflexible rule of conduct that applies not only to the defendant in the case before it but also to all defendants in future cases who are confronted by a risk of the same type of harm to another, regardless of differences in the surrounding circumstances. For good reason, most courts have rejected this course.
When courts impose a duty on a defendant, they generally do so without imposing a rigid, specific, and inflexible course of conduct. “In most cases, courts have fixed no standard of care for tort liability more precise than that of a reasonably prudent person under like circumstances.” (Ramirez v. Plough, Inc., supra, 6 Cal.4th 539, 546.) As this court has recognized, the reasonable person standard on which negligence liability is founded necessarily requires an individualized examination of a particular course of conduct and an individualized determination of its reasonableness. “What constitutes ‘ordinary care’ under the facts of any particular case is usually a question for the jury, which must view the conduct as a whole in the light of all the circumstances. Thus, it is common practice for the jmy to determine the standard of conduct to be applied within the compass of the broad rule that the prescribed conduct must conform to that of a ‘reasonably prudent [person] under the circumstances.’ ” (Laird v. T. W. Mather, Inc. (1958) 51 Cal.2d 210, 215 [331 P.2d 617]; see also Lucas v. Southern Pacific Co. (1971) 19 Cal.App.3d 124, 137-140 [96 Cal.Rptr. 356]; Weiner, The Civil Jury Trial and the Law-Fact Distinction, supra, 54 Cal.L.Rev. 1867, 1883-1885.)
*840There are at least three good reasons why negligence law has allocated the judgment of the reasonableness of a defendant’s conduct to the jury as a matter for case-by-case determination, rather than having courts, under the rubric of “duty,” establish as a matter of law fixed and unvarying rules of conduct for various categories of human activity. The first reason arises from the irreducible variety of circumstances which may surround an event that causes harm to someone. Because of this variety, an individualized rather than categorical determination of what constitutes reasonable care to avoid a particular type of harm usually will provide a more precise measure of what conduct is reasonable under the circumstances. (Prosser & Keeton on Torts, supra, § 37, p. 237 [“Since it is impossible to prescribe definite rules in advance for every combination of circumstances which may arise, the details of the standard must be filled in in each particular case.”].)
This court in the past has repeatedly recognized that judging the reasonableness of a defendant’s conduct on a case-by-case basis provides a more precise determination of the contours of liability: “Standards of care are typically relative; rules of law are basically absolute. Hence, in regard to negligence, any attempt to screen factual conduct into legal classifications through a sieve of absolute law will be impracticable whenever the related circumstances admit of materially conflicting inferences. In other words, the actor’s conduct must always be gauged in relation to all the other material circumstances surrounding it . . . (Toschi v. Christian, supra, 24 Cal.2d 354, 360.)
“If the term ‘negligence’ signified an absolute quantity or thing to be measured in all cases in accordance with some precise standard, much of the difficulty which besets courts in the solution of this class of cases would be at once dissipated. But, unfortunately, it does not. Negligence is not absolute, but is a thing which is always relative to the particular circumstances of which it is sought to be predicated. For this reason it is very rare that a set of circumstances is presented which enables a court to say as matter of law that negligence has been shown. As a very general rule, it is a question of fact for the jury—an inference to be deduced from the circumstances . . . .” (Fox v. Oakland Con. St. Ry. (1897) 118 Cal. 55, 61-62 [50 P. 25]; see also Seller v. Market-Street Ry. Co. (1903) 139 Cal. 268, 271 [72 P. 1006] [Negligence “is a question of fact for the jury, an inference to be deduced from the circumstances of each particular case, and it is only where the deduction to be drawn is inevitably that of negligence that the court is authorized to withdraw the question from the jury.”].)
The greater accuracy that results from determining the propriety of the defendant’s conduct by application of the reasonable person standard of care *841advances the economic function of tort law. The reasonable person standard of negligence liability, by asking whether a reasonable person would have taken additional precautions under the circumstances, examines how the risk of harm from the defendant’s activity and the benefits of conducting the activity vary depending upon the precautions taken to avoid the harm. (See Landes & Posner, The Economic Structure of Tort Law (1987) pp. 58-65, 85-87; see also Weirum v. RKO General, Inc. (1975) 15 Cal.3d 40, 47 [123 Cal.Rptr. 468, 539 P.2d 36] [“Liability is imposed only if the risk of harm resulting from the act is deemed unreasonable—i.e., if the gravity and likelihood of the danger outweigh the utility of the conduct involved.”]; Prosser & Keeton on Torts, supra, § 31, p. 173 & fn. 46.) In economic terms, it encourages the optimal level of care on the part of both victims and injurers, optimal being defined as the point at which the cost of any additional precautions will be greater than the benefit of avoiding additional injury. (See Landes & Posner, The Economic Structure of Tort Law, supra, pp. 58-65, 85-87; Prosser & Keeton on Torts, supra, § 31, p. 173 & fn. 46.) An individualized determination of reasonableness increases efficiency because it allows for the optimal level of care to be determined under the circumstances of each case; it asks not whether in general the cost of additional precautions would be greater than the cost of additional injuries but whether, under the specific circumstances of the case at hand, additional precautions would have been cost effective. (It asks this question, of course, not formally but intuitively by asking whether a reasonable person would have taken additional precautions to avoid the accident. See Landes & Posner, The Economic Structure of Tort Law, supra, pp. 23, 85-87, 96-107; Weirum v. RKO General, Inc., supra, 15 Cal.3d 40, 47.) To fix the conduct required to avoid a given harm as an absolute standard that does not vary with the accompanying circumstances, as the majority does here, inevitably means that in numerous cases the law will require something other than optimal care. (See Prosser & Keeton on Torts, supra, § 31, p. 173 [Because of the cost-benefit balancing required by the reasonable person standard, “it is usually very difficult, and often simply not possible, to reduce negligence to any definite rules; it is ‘relative to the need and the occasion,’ and conduct which would be proper under some circumstances becomes negligence under others.” (Fns. omitted.)].)
There is a second reason why it is preferable to leave the question of what conduct is required under the circumstances to the jury for an individualized determination, rather than attempting to mandate detailed rules of conduct categorically. Doing so allows successive juries to reassess what precautions are reasonable as social, economic, and technological conditions change over time: “[R]oom is left for a change of standard when a change in the physical *842conditions of life, or a change in the public valuation of the respective interests concerned, require it.” (Bohlen, Mixed Questions of Law and Fact (1924) 72 U. Pa. L.Rev. 111, 117; see also id. at pp. 119-120.) Accordingly, the reasonable person standard of care, because it does not dictate a fixed course of conduct to avoid the harm in question, encourages innovations that reduce the cost of precautions and substitutions of less costly preventative measures that are equally or more effective in avoiding the harm. By contrast, locking defendants forever into a straitjacket of prescribed conduct removes the incentive for them to lower the cost and increase the level of precautions they provide.
The third reason for allocating the determination of the reasonableness of defendant’s care to the jury in a negligence case is that the jury, in addition to providing an individualized judgment of defendant’s conduct, also has the potential to bring a wider array of practical experience and knowledge to that task than could a single individual such as a judge. The jury is a repository of collective wisdom and understanding concerning the conditions and circumstances of everyday life that it can bring to bear on the determination of what conduct is reasonable. As the conscience of the community, the jury plays an essential role in the application of the reasonable person standard of care. (See Prosser & Keeton on Torts, supra, § 32, p. 175 [the “reasonable person” is “a personification of a community ideal of reasonable behavior, determined by the jury’s social judgment”]; id., § 37, p. 237 [“the public insists that its conduct be judged in part by the [person] in the street rather than by lawyers, and the jury serves as a shock-absorber to cushion the impact of the law”].) Accordingly, “the questions of the reasonableness of the risk of harm and the application of the standard of due care to particular facts are mixed questions of law and fact (or questions of Taw application’ [citation]) which we have traditionally regarded as better answered by juries,” rather than judges. (Schwartz v. Helms Bakery Limited (1967) 67 Cal.2d 232, 237, fn. 3 [60 Cal.Rptr. 510, 430 P.2d 68].)
Indeed, this court long ago recognized the value that a jury adds to the determination of reasonable care in a negligence case: “Our ideas as to what would be proper care vary according to temperament, knowledge, and experience. A party should not be held to the peculiar notions of the judge as to what would be ordinary care. That only can be regarded as a standard or rule which would be recognized or enforced by all learned and conscientious judges, or could be formulated into a rule. In the nature of things no such common standard can be reached in cases of negligence, where reasonable [persons] can reach opposite conclusions upon the facts. In such cases it was said in Mann v. Baltimore etc. R. R. Co., 128 Ind. 138: ‘It is said to be the *843highest effort of the law to obtain the judgment of twelve [persons] of the average of the community, comprising [individuals] of learning, [individuals] of little education, [individuals] whose learning consists only of what they have themselves seen and heard, the merchant, mechanic, the farmer, and laborer, as to whether negligence does or does not exist in the given case.’ ” (Herbert v. Southern Pacific Co. (1898) 121 Cal. 227, 229 [53 P. 651]; see also Lucas v. Southern Pacific Co., supra, 19 Cal.App.3d 124, 137 [“Appellate edicts fixing the conduct of reasonably careful [persons] . . . infringe on the jury’s power to decide what amounts to reasonable care.”].)
The United States Supreme Court has similarly noted the unique practical knowledge that a jury in a negligence case brings to the task of judging the reasonableness of conduct: “Twelve [persons] of the average of the community ... sit together, consult, apply their separate experience of the affairs of life to the facts proven, and draw a unanimous conclusion. This average judgment thus given it is the great effort of the law to obtain. It is assumed that twelve [persons] know more of the common affairs of life than does one [individual], that they can draw wiser and safer conclusions from admitted facts . . . than can a single judge. [•][]... [Although the facts are undisputed it is for the jury and not for the judge to determine whether proper care was given, or whether they establish negligence.” (Railroad Company v. Stout (1873) 84 U.S. (17 Wall.) 657, 664 [21 L.Ed. 745, 749].)4
The majority here, in the course of ignoring the boundary that our decisions have established between issues of duty to be determined by the court and issues of the reasonableness of the defendant’s conduct to be determined by the jury, asserts that its holding will result in fewer robberies and is therefore preferable as a matter of policy. This assertion lacks merit. It rests on the premise that in the absence of any potential liability to patrons, business proprietors will not only refuse the demands of robbers more frequently but that their refusal to cooperate will in many cases discourage robbers by successfully denying the robbers whatever thing of value they seek. As the ultimate success of the robber in this case illustrates, however, it is unlikely that in most cases a proprietor’s refusal to cooperate will deny the robber what he seeks. It also seems unlikely that the majority’s decision will embolden business proprietors or their employees to refuse the demands *844of an armed robber at a greater rate than they would if they were under a duty to use reasonable care, for they too are in the robber’s zone of danger.5
I would instead adhere to the traditional division between duty and standard of care established by our precedents. Under that division, the issue here is whether KFC and its employees breached the standard of care by unreasonably refusing to comply with the robber’s initial demand for money, not whether as a matter of law they have a duty to comply with a robber’s demand in every case. For the reasons I have stated earlier, KFC has not demonstrated that no rational juror could conclude that KFC’s cashier acted unreasonably in refusing the robber’s demand and attempting to fool the robber; accordingly, it has not demonstrated that it is entitled to summary judgment on this ground.
Conclusion
The majority, by mischaracterizing the issue in this case as whether a defendant business proprietor has a “duty” to comply with the demands of a robber, seeks refuge in the simplicity of a categorical pronouncement. As the discussion above demonstrates, however, our prior decisions have correctly allocated the question of the reasonableness of a defendant’s conduct to the jury for an individualized determination made by applying the reasonable person standard to the circumstances of the case, rather than to the court for a categorical determination applicable to all defendants under all circumstances. That allocation is appropriate here as well.
It would seem likely that in most cases a business proprietor’s initial refusal to comply with a robber’s demand followed by immediate compliance with the demand when the robber reiterated it would not be unreasonable, in light of the stress, surprise, and uncertainty that would attend the proprietor’s decision as to how to respond to the robber. But neither I nor the majority can answer that question categorically with assurance, for none of us can anticipate all of the myriad variations in circumstance in which the issue may arise. Just as it cannot be said that as a matter of law it is always *845(or never) negligent for a doctor to fail to give penicillin to a patient with a fever, it cannot be said as a matter of law that it is never (or always) negligent for a business proprietor to increase the peril to a customer by failing to comply with a robber’s demand. Having determined that business proprietors must act reasonably to protect their customers from harm caused by third parties, this court should leave for the jury the determination of whether the conduct of KFC and its employees in this particular instance conforms to that standard.
Therefore, for the reasons stated above, I would affirm the judgment of the Court of Appeal denying KFC’s petition for a writ of mandate.
Werdegar, J., concurred.
Liability also, of course, requires a third determination: Was the defendant’s failure to conform to the standard of care the proximate or legal cause of the plaintiff’s injury? (See Ann M. v. Pacific Plaza Shopping Center, supra, 6 Cal.4th 666, 673.) That question is not before us in this case.
As the majority notes, appellate courts, following their experience in deciding many negligence claims arising from a particular activity whose circumstances do not vary greatly, on rare occasions have concluded that the reasonable course of conduct for that activity could be declared in a judicial decision as a detailed rule of reasonable conduct. (Ramirez v. Plough, Inc., supra, 6 Cal.4th 539, 547; Rest.2d Torts, § 285, com. e, p. 22.) In such a case, whether the defendant was negligent turns on whether the defendant followed the rule of conduct laid down by judicial decision.
The majority here, however, does not create a fixed rule of reasonable conduct for juries to apply. It does not claim that robberies are so stereotypical and judicial experience with them so vast that it is feasible to define reasonable conduct during a robbery by a fixed rule. It does not purport to conclude that there are no circumstances in which a reasonable business proprietor would ever comply with a robber’s demands (nor is there any basis on which it could reach such a conclusion). Rather, it decides that the reasonableness of the proprietor’s conduct is irrelevant because the proprietor has no duty to act to protect its innocent patrons during a robbery. Duty, not reasonableness, is the analysis the majority adopts in this case.
Moreover, as a leading torts treatise observes, most attempts to create such judicial rules of reasonable conduct have failed: “Almost invariably the rule has broken down in the face of the necessity of basing the standard [of reasonable conduct] upon the particular circumstances, the apparent risk, and the actor’s opportunity to deal with it.” (Prosser & Keeton on Torts, supra, § 35, p. 218.) Because the duty imposed by negligence law “requires only conduct proportionate to the circumstances and the risk[, it] seldom, if ever, can be made a matter of absolute rule.” (Id., at p. 219, fn. omitted.) For instance, the archetypal example of this practice was the attempt of various appellate courts to precisely define the proper conduct of a locomotive engineer and an automobile driver as each approached an unguarded grade crossing. (Rest.2d Torts, § 285, com. e, p. 22.) The United States Supreme Court, in a famous pair of decisions, first created a rule of conduct for that activity and then abandoned it, ultimately concluding that notwithstanding the relatively narrow range of factual variation in railroad crossing cases, the reasonable person standard was a better tool for determining negligence. (B. & O. R. R. v. Goodman (1927) 275 U.S. 66, 70 [72 L.Ed. 167, 168, 48 S.Ct. 24, 56 A.L.R. 645]; Pokora v. Wabash Ry. Co. (1934) 292 U.S. 98, 105-106 [78 L.Ed. 1149, 1154-1155, 54 S.Ct. 580, 91 A.L.R. 1049]; accord, Toschi v. Christian (1944) 24 Cal.2d 354, 360 [149 P.2d 848].)
A leading torts treatise makes this point: “It is quite possible, and not at all uncommon, to deal with most of the questions which arise in a negligence case in terms of ‘duty.’ . . . But the problems of ‘duty’ are sufficiently complex without subdividing it in this manner to cover an endless series of details of conduct. It is better to reserve ‘duty’ for the problem of the relation between individuals which imposes upon one a legal obligation for the benefit of the other, and to deal with particular conduct in terms of a legal standard of what is required to meet the obligation. In other words, ‘duty’ is a question of whether the defendant is under any obligation for the benefit of the particular plaintiff; and in negligence cases, the duty is always the same—to conform to the legal standard of reasonable conduct in the light of the apparent risk. What the defendant must do, or must not do, is a question of the standard of conduct required to satisfy the duty.” (Prosser & Keeton on Torts, supra, § 53, p. 356; see also Coffee v. McDonnell-Douglas Corp., supra, 8 Cal.3d 551, 559, fn. 8.)
The values underlying the preference for having juries in negligence cases decide what level of precautions is reasonable under the circumstances in some respects parallel the values underlying the right to a jury trial guaranteed in criminal cases by Sixth Amendment to the United States Constitution. Both sets of values reflect in part a belief that certain decisions are best left to the commonsense judgment of the jury. (See People v. Marshall (1996) 13 Cal.4th 799, 877 [55 Cal.Rptr.2d 347, 919 P.2d 1280] (conc, and dis. opn. of Kennard, J.); see also Amar, The Bill of Rights as a Constitution (1991) 100 Yale L.J. 1131, 1182-1199.)
The majority also asserts that holding a business proprietor liable for refusing to comply with a robber’s demand “would be inconsistent with the public policy [permitting the use of force in defense of property] reflected in article I, section 1 of the California Constitution and Civil Code section 50.” (Maj. opn., ante, at p. 829.) As the majority acknowledges, KFC and its employees did not use any force to defend property in this case; thus, those provisions are not implicated here and KFC does not assert that its conduct is privileged under those sections. More fundamentally, as Justice Mosk observes in his dissent, ante, the notion that article I, section 1 of the California Constitution and Civil Code section 50 automatically excuse a person exercising those rights from the obligation to do so in a manner that does not unreasonably cause harm to others is wrong.