Causation in Criminal Law Research Paper

It is sometimes urged that omission liability (that is, liability for not doing an act required by law) is noncausal, and there is a sense in which this is true. A defendant who omits to do an act the law requires him to do is not liable for having caused the harm that the act omitted would have prevented; rather, he is liable for not preventing the harm (Moore, 1993, pp. 267–278). Yet notice that to assess whether a defendant is liable for an omission to prevent some harm, a causal judgment is still necessary: we have to know that no act of the defendant prevented (i.e., caused the absence of) any such harm. For if some act of the defendant did cause the absence of a certain harm, then the defendant cannot be said to have omitted to have prevented the harm. One can, for example, only be liable for omitting to save another from drowning if none of one’s acts have the causal property, saving-the-other-fromdrowning (Moore, 1993, pp. 29–31).

It is also sometimes said that many prohibitions of the criminal law do not involve causation. Criminal law typically prohibits theft, rape, burglary, conspiracy, and attempt, and (so the argument goes) these are types of actions that have no causal elements in them. Although this view has been elevated to a dogma accepted by both American and English criminal law theorists (Fletcher, 1978, pp. 388–390; Fletcher, 1998, pp. 60–62; Buxton, p. 18; Williams, p. 368), it is manifestly false. A theft occurs, for example, only when an actor’s voluntary act causes movement (‘‘asportation’’) of the goods stolen. Similarly a burglary occurs only when there is a breaking and an entering of a building, and these occur only when a defendant’s voluntary act causes a lock on a window to be broken and causes the alleged burglar to be in the building in question (Moore, 1993, pp. 213–225). The temptation to accept the dogma (of noncausal criminal actions) stems from the fact that many of the results the criminal law prohibits are usually brought about rather directly. Penetration in rape, for example, usually is not the result of a lengthy chain of events beginning with the rapist’s voluntary act. But this is not always the case, as where the defendant inserts the penis of another into the victim (Dusenberry v. Commonwealth, 220 Va. 770, 263 S.E2d 392(1980)); and in any case, that the causal conclusion is often easy to reach should not obscure the fact that a causal judgment is involved in all actions prohibited or required by the criminal law.

The Place of Causation in Criminal Law Policy

It is a much debated question whether the criminal law should be so result-oriented. Why is the defendant who intends to kill another and does all he can to succeed in his plan less punishable when he fails to cause the harm intended than when he succeeds? Utilitarians about punishment typically justify this causation-oriented grading scheme by alluding either to popular sentiment or to the need to give criminals incentives not to try again. Retributivists about punishment typically invoke a notion of ‘‘moral luck’’ according to which a defendant’s moral blameworthiness increases with success in his criminal plans (Moore, 1997, pp. 191–247). In any case, for one set of reasons or another, causation is an element of criminal liability for all completed crimes, in addition to mens rea and voluntariness of action.

Causation in Criminal Law and Causation in Tort Law

Many of the leading cases on causation, most of the causal doctrines finding some acceptance in the law, and most of the theorizing about causation, originate in the law of tort and not in the criminal law. The reasons for this are not hard to discern. Unlike the thousands of specific actions prohibited or required by the criminal law, tort law largely consists of but one injunction: do not unreasonably act so as to cause harm to another. Such an injunction places greater weight on causation. It leaves open a full range of causal questions, much more than do injunctions of criminal law such as, ‘‘do not intentionally hit another.’’

Criminal law thus has been a borrower from torts on the issue of causation. Such borrowing has not been uniform or without reservations. Aside from the greater demands of directness of causation implicit in specific criminal prohibitions (noted above), the criminal sanction of punishment is sometimes said to demand greater stringency of causation than is demanded by the less severe tort sanction of compensation. Still, the usual form such reservations take is for criminal law to modify causation doctrines in tort by a matter of degree only (Moore, 1997, p. 363 n.1). Foreseeability, for example, is a test of causation in both fields, but what must be foreseeable, and the degree with which it must be foreseeable, is sometimes thought to be greater in criminal law than in torts. Such variation by degree only has allowed causation in criminal law and in torts to be discussed via the same tests, which we shall now do.

Conventional Analysis of Causation in The Law

The Two-Step Analysis

The conventional wisdom about the causation requirement in both criminal law and torts is that it in reality consists of two very different requirements. The first requirement is that of ‘‘cause-in-fact.’’ This is said to be the true causal requirement because this doctrine adopts the scientific notion of causation. Whether cigarette smoking causes cancer, whether the presence of hydrogen or helium caused an explosion, are factual questions to be resolved by the best science the courts can muster. By contrast, the second requirement, that of ‘‘proximate’’ or ‘‘legal’’ cause, is said to be an evaluative issue, to be resolved by arguments of policy and not arguments of scientific fact. Suppose a defendant knifes his victim, who then dies because her religious convictions are such that she refuses medical treatment. Has such a defendant (legally) caused her death? The answer to such questions, it is said, depends on the policies behind liability, not on any factual issues.

The Counterfactual Analysis of Cause-in-Fact

By far the dominant test for cause-in-fact is the common law and Model Penal Code ‘‘sine qua non,’’ or ‘‘but-for’’ test (MPC §2.03(1)). Such a test asks a counterfactual question: ‘‘but for the defendant’s action, would the victim have been harmed in the way the criminal law prohibits?’’ This test is also sometimes called the necessary condition test, because it requires that the defendant’s action be necessary to the victim’s harm. The appeal of this test stems from this fact. The test seems to isolate something we seem to care a lot about, both in explaining events and in assessing responsibility for them, namely, did the defendant’s act make a difference? Insofar as we increase moral blameworthiness and legal punishment for actors who do cause bad results (not just try to), we seemingly should care whether a particular bad result would have happened anyway, even without the defendant.

The Policy Analysis of Legal Cause

There is no equivalently dominant test of legal or proximate cause. There are nonetheless four distinguishable sorts of tests having some authority within the legal literature. The first of these are what we may call ‘‘ad hoc policy tests’’ (Edgarton). The idea is that courts balance a range of policies in each case that they adjudicate where a defendant has been found to have caused-in-fact a legally prohibited harm. They may balance certain ‘‘social interests’’ like the need for deterrence with certain ‘‘individual interests’’ like the unfairness of surprising a defendant with liability. Courts then decide wherever such balance leads. Whatever decision is reached on such case-by-case policy balancing is then cast in terms of ‘‘proximate’’ or ‘‘legal’’ cause. Such labels are simply the conclusions of policy balances; the labels have nothing to do with causation in any ordinary or scientific sense.

The second sort of test here is one that adopts general rules of legal causation. Such rules are adopted for various policy reasons also having nothing to do with causation, but this ‘‘rules-based’’ test differs from the last by its eschewal of case-by-case balancing; rather, per se rules of legal causation are adopted for policy reasons. Thus, the common law rule for homicide was that death must occur within a year and a day of the defendant’s harmful action, else the defendant could not be said to have legally caused the death. Analogously, the ‘‘last wrongdoer rule’’ held that when a single victim is mortally wounded by two or more assailants, acting not in concert and acting seriatim over time, only the last wrongdoer could be said to be the legal cause of the death (Smith, p. 111). Such sorts of tests also found a temporary home in tort law with its ‘‘first house rule,’’ according to which a railroad whose negligently emitted sparks burned an entire town was only liable for the house or houses directly ignited by its sparks, not for other houses ignited by the burning of those first burnt houses (Ryan v. New York Central R.R., 35 N.Y. 210, 91 Am. Dec.49 (1866)). There is no pretense in such rules of making truly causal discriminations; rather, such rules were adopted for explicit reasons of legal policy.

The third sort of test here is the well-known foreseeability test (Moore, 1997, pp. 363–399). Unlike the ‘‘rules-based’’ test, here there is no multiplicity of rules for specific situations (like homicide, intervening wrongdoers, railroad fires, etc.). Rather, there is one rule universally applicable to all criminal cases: was the harm that the defendant’s act in fact caused foreseeable to him at the time he acted? This purportedly universal test for legal causation is usually justified by one of two policies: either the unfairness of punishing someone for harms that they could not foresee, or the inability to gain any deterrence by punishing such actors (since the criminal law’s threat value is nonexistent for unforeseeable violations).

Some jurisdictions restrict the foreseeability test to one kind of situation. When some human action or natural event intervenes between the defendant’s action and the harm, the restricted test asks whether that intervening action or event was foreseeable to the defendant when he acted (Moore, 1997, p. 363 n.1). This restricted foreseeability test is like the restricted rules we saw before and is unlike the universal test of legal causation the foreseeability test usually purports to be.

The fourth and last sort of test here is the ‘‘harm-within-the-risk’’ test (Green). Like the foreseeability test, this test purports to be a test of legal cause universally applicable to all criminal cases. This test too is justified on policy grounds and does not pretend to have anything to do with factual or scientific causation. Doctrinally, however, the test differs from a simple foreseeability test.

Consider first the arena from which the test takes its name, crimes of risk creation. If the defendant is charged with negligent homicide, for example, this test requires that the death of the victim be within the risk that made the actor’s action negligent. Similarly, if the charge is manslaughter (for which consciousness of the risk is required in some jurisdictions), this test requires that the death of the victim be within the risk the awareness of which made the defendant’s action reckless.

Extension of this test to non-risk-creation crimes requires some modification. For crimes of strict liability, where no mens rea is required, the test requires that the harm that happened be one of the types of harms the risk of which motivated the legislature to criminalize the behavior. For crimes requiring knowledge or general intention for their mens rea, the test asks whether the harm that happened was an instance of the type of harm foreseen by the defendant as he acted. For crimes requiring purpose or specific intent for their mens rea, the test asks whether the harm that happened was an instance of the type of harm the defendant intended to achieve by his action.

What motivates all of these variations of the harm-within-the-risk test is the following insight: when assessing culpable mens rea, there is always a ‘‘fit problem’’ (Moore, 1997, pp. 469–476). Suppose a defendant intends to hit his victim in the face with a stick; suppose further he intends the hit to put out the victim’s left eye. As it happens, the victim turns suddenly as he is being hit, and loses his right ear. Whether the harm that happened is an instance of the type of harm intended is what the present author calls the ‘‘fit problem.’’ Fact finders have to fit the mental state the defendant had to the actual result he achieved and ask whether it is close enough for him to be punished for a crime of intent like mayhem. (If it is not close enough, then he may yet be convicted of some lesser crime of battery or reckless endangerment.)

The essential claim behind the harm within the risk test is that ‘‘legal cause’’ is the inapt label we have put on a problem of culpability, the fit problem. Proponents of this test urge that legal cause, properly understood, is really a mens rea doctrine, not a doctrine of causation at all.

Problems with The Conventional Analysis

Problems with The Counterfactual Test

Very generally there are four sorts of problems with the counterfactual test for causation in fact. One set of these problems has to do with proof and evidence. As an element of the prima facie case, causation-in-fact must be proven by the prosecution beyond a reasonable doubt. Yet counterfactuals by their nature are difficult to prove with that degree of certainty, for they require the fact finder to speculate what would have happened if the defendant had not done what he did. Suppose a defendant culpably destroys a life preserver on a seagoing tug. When a crewman falls overboard and drowns, was a necessary condition of his death the act of the defendant in destroying the life preserver? If the life preserver had been there, would anyone have thought to use it? Thrown it in time? Thrown it far enough? Have gotten near enough to the victim that he would have reached it? We often lack the kind of precise information that could verify whether the culpable act of the defendant made any difference in this way.

A second set of problems stems from an indeterminacy of meaning in the test, not from difficulties of factual verification. There is a great vagueness in counterfactual judgments. The vagueness lies in specifying the possible world in which we are to test the counterfactual (Moore, 1997, pp. 345–347). When we say, ‘‘but for the defendant’s act of destroying the life preserver,’’ what world are we imagining? We know we are to eliminate the defendant’s act, but what are we to replace it with? A life preserver that was destroyed by the heavy seas (that themselves explain why the defendant couldn’t destroy the life preserver)? A defendant who did not destroy the life preserver because he had already pushed the victim overboard when no one else was around to throw the life preserver to the victim? And so on. To make the counterfactual test determinate enough to yield one answer rather than another, we have to assume that we share an ability to specify a possible world that is ‘‘most similar’’ to our actual world, and that it is in this possible world that we ask our counterfactual question (Lewis, 1970).

The third and fourth sets of problems stem from the inability of the counterfactual test to match what for most of us are firm causal intuitions. The third set of problems arise because the counterfactual test seems too lenient in what it counts as a cause. The criticism is that the test is thus overinclusive. The fourth set of problems arise because the counterfactual test seems too stringent in what it counts as a cause. The criticism here is that the test is underinclusive.

The overinclusiveness of the test can be seen in at least four distinct areas. To begin with, the test fails to distinguish acts from omissions, in that both can be equally necessary to the happening of some event (Moore, 1993, pp. 267–278; Moore, 1999). Thus, on the counterfactual test both my stabbing the victim through the heart and your failure to prevent me (though you were half a world away at the time) are equally the cause of the victim’s death. This is, to put it bluntly, preposterous.

It is important to see that there is a counterfactual question to ask about omissions before we blame someone for them. We do need to know, counterfactually, if the defendant had not omitted to do some action, whether that action would have prevented the harm in question. Yet the counterfactual test of causation would turn this question about an ability to prevent some harm, into a question of causing that which was not prevented. It is a significant objection to the counterfactual theory that it blurs this crucial distinction.

A second way in which the counterfactual test is overinclusive is with regard to coincidences. Suppose a defendant culpably delays his train at t₁; much, much later and much further down the track at t₂, the train is hit by a flood, resulting in damage and loss of life (Denny v. N.Y. Central R.R., 13 Gray (Mass.) 481 (1859)). Since but for the delay at t₁, there would have been no damage or loss of life at t₂, the counterfactual test yields the unwelcome result that the defendant’s delaying caused the harm.

While such cases of overt coincidences are rare, they are the tip of the iceberg here. Innumerable remote conditions are necessary to the production of any event. Oxygen in the air over England, timber in Scotland, Henry the VIII’s obesity, and Drake’s perspicacity were all probably necessary for the defeat of the Spanish Armada (Moore, 1993, pp. 268–269), but we should be loath to say that each of these was equally the cause of that defeat.

A third area of overinclusiveness stems from the rockbed intuition that causation is asymmetrical with respect to time (Moore, 1999). My dynamite exploding at t₁ may cause your mother minks to kill their young at t₂, yet your mother minks killing their young at t₂ did not cause my dynamite to explode at t₁. The counterfactual test has a difficult time in accommodating this simple but stubborn intuition.

To see this, recall the logic of necessary and sufficient conditions. If event c is not only necessary for event e but also sufficient, then (of necessity) e is also necessary for c. In such a case c and e are symmetrically necessary conditions for each other and, on the counterfactual analysis, each is therefore the cause of the other. Intuitively we know that this is absurd, yet to avoid this result we must deny that some cause c is ever sufficient (as well as necessary) for some effect e. And the problem is that almost all proponents of the necessary condition test readily admit that every cause c is, if not sufficient by itself, then sufficient when conjoined with certain other conditions c’; c”, etc. (Mill, 1965, book 3, chap. 5, sec. 3). Sufficiency seems to well capture the commonsense view that causes make their effects inevitable. Yet, with such inevitability of effects from their causes come a necessity of those effects for those causes. Therefore, every effect is also a cause of its cause?

The fourth sort of overinclusiveness of the counterfactual analysis can be seen in cases of epiphenomena. One event is epiphenomenal to another event when both events are effects of a common cause (Moore, 1999). I jog in the morning with my dog. This has two effects: at t₂, my feet get tired; at t₃, my dog gets tired. Intuitively we know that my feet getting tired did not cause my dog to get tired. Yet the counterfactual analysis suggests just the opposite. My jogging in the morning was not only necessary for my feet getting tired, it (sometimes at least) was also sufficient. This means (see above) that my feet getting tired was necessary to my jogging in the morning. Yet we know (on the counterfactual analysis) that my jogging in the morning was necessary to my dog getting tired. Therefore, by the transitivity of ‘‘necessary,’’ my feet getting tired was necessary to my dog getting tired. Therefore, the tiring of my feet did cause the tiring of my dog, contrary to our firm intuitions about epiphenomena.

The fourth set of problems for the counterfactual test has to do with the test’s underinclusiveness. Such underinclusiveness can be seen in the well-known overdetermination cases (Moore, 1999; Wright, 1985, pp. 1775–1798), where each of two events c₁ and c₂ is independently sufficient for some third event e; logically, this entails that neither c₁ nor c₂ is necessary for e, and thus, on the counterfactual analysis of causation, neither can be the cause of e. Just about everybody rejects this conclusion, and so such cases pose a real problem for the counterfactual analysis.

There are two distinct kinds of overdetermination cases. The first are the concurrentcause cases: two fires, two shotgun blasts, two noisy motorcycles, each are sufficient to burn, kill, or scare some victim. The defendant is responsible for only one fire, shot, or motorcycle. Yet his fire, shot, or noise joins the other one, and both simultaneously cause some single, individual harm. On the counterfactual analysis the defendant’s fire, shot, or noise was not the cause of any harm because it was not necessary to the production of the harm—after all, the other fire, shot, or noise was by itself sufficient. Yet the same can be said about the second fire, shot, or noise. So, on the but-for test, neither was the cause! And this is absurd.

The preemptive kind of overdetermination cases are different. Here the two putative causes are not simultaneous but are temporally ordered. The defendant’s fire arrives first and burns down the victim’s building; the second fire arrives shortly thereafter, and would have been sufficient to have burned down the building, only there was no building to burn down. Here our intuitions are just as clear as in the concurrent overdetermination cases but they are different: the defendant’s fire did cause the harm, and the second fire did not. Yet the counterfactual analysis again yields the counterintuitive implication that neither fire caused the harm because neither fire was necessary (each being sufficient) for the harm.

Situated rather nicely between these two sorts of overdetermination cases is what this author has called the asymmetrical overdetermination cases (Moore, 1999). Suppose the defendant nonmortally stabs the victim at the same time as another defendant mortally stabs the same victim; the victim dies of loss of blood, most of the blood gushing out of the mortal wound. Has the nonmortally wounding defendant caused the death of the victim? Not according to the counterfactual analysis: given the sufficiency of the mortal wound, the nonmortal wound was not necessary for, and thus not a cause of, death. This conclusion is contrary to common intuition as well as legal authority (People v. Lewis, 124 Cal. 551, 57 P. 470 (1899)).

Defenders of the counterfactual analysis are not bereft of replies to these objections. As to problems of proof they assert that counterfactuals are no harder to verify than other judgments applying causal laws to unobservable domains (such as those parts of the past for which there is no direct evidence, or those aspects of the universe too far removed for us to observe, or those future events beyond our likely existence). As to the problem of indeterminacy, they assert that we test counterfactuals in that possible world that is relatively close to our actual world; usually this means removing the defendant’s action only, and then suspending enough causal laws so that events that normally cause such action just did not on this occasion (Wright, 1988). As to the problems of omissions and asymmetry through time, they assert that we should simply stipulate that a cause is not only a necessary condition for its effect, but it is also an event (not the absence of an event) that precedes (not succeeds) the event which is its effect. Such stipulations are embarrassingly ad hoc, but they do eliminate otherwise troublesome counterexamples. With regard to coincidences and epiphenomenal pairs of events, they assert that there are no causal laws connecting classes of such events with one another; one type of event is not necessary for another type of event, however necessary one particular event may be for its putative (coincidental or epiphenomerical) ‘‘effect.’’ With regard to the embarrassment of riches in terms of how many conditions are necessary for any given event or state, they typically bite the bullet and admit that causation is a very nondiscriminating relation; however our usage of ‘‘cause’’ is more discriminating by building in pragmatic restrictions on when certain information is appropriately imparted to a given audience. As to the problem posed by the concurrent overdetermination cases, they usually urge that if one individuates the effect finely enough in such cases, one will see that each concurrent cause is necessary to that specific effect (American Law Institute, 1985). A two-bullet death is different than a one-bullet death, so that each simultaneous, mortally wounding bullet is necessary to the particular death (i.e., a two-bullet death) suffered by the victim shot by two defendants. Similarly, in the preemptive overdetermination cases, they assert that the first fire to arrive was necessary to the burning of the house, but the second was not, because had the first fire not happened the second fire still would have been prevented from burning the house (Lewis, 1970).

There are deep and well-known problems with all of these responses by the counterfactual theorists (Moore, 1999). Rather than pursue these, we should briefly consider modifications of the counterfactual test designed to end run some of these problems. With regard to the problem posed by the overdetermination cases, the best known alternative is to propose the NESS test: an event c causes an event e if and only if c is a necessary element in a set of conditions sufficient for e (Mackie; Wright, 1985). It is the stress on sufficiency that is supposed to end run the overdetermination problems. In the concurrent cause cases, where the two fires join to burn the victim’s house, each fire is said to be a necessary element of its own sufficient set, so each fire is a cause. In the pre-emptive case, where the fires do not join and one arrives first, the first fire is a necessary element of a sufficient set, and so is the cause; but the second fire is not because absent from its set is the existence of a house to be burned.

There are problem with this NESS alternative too (Moore, 1999). For example, it is not stated how one individuates sets of conditions. Why aren’t the two fires part of the same set, in which event neither is necessary? Also, in the preemptive case, isn’t the addition of the condition, ‘‘existence of the victim’s house at the time the second fire would be sufficient to destroy it,’’ already sliding in the causal conclusion that the first fire already caused the house not to exist? Again these problems are not conclusive, and debate about them will no doubt continue for the foreseeable future. Such problems cause grave doubt to exist about any version of the counterfactual test among many legal theoreticians. Such academic doubts seem to have shaken the doctrinal dominance of the test very little, however.

Problems with The Policy Tests for Legal Cause

The main problem with both the ad hoc and the rule-based policy tests is that they seek to maximize the wrong policies. The general ‘‘functionalist’’ approach of such tests to legal concepts is correct: we should always ask after the purpose of the rule or institution in which the concept figures in order to ascertain its legal meaning. Yet the dominant purpose of the law’s concept of causation is to grade punishment proportionately to moral blameworthiness. One who intentionally or recklessly causes a harm that another only tries to cause or risks causing, is more blameworthy (Moore, 1997, pp. 191–247). We must thus not seek the meaning of causation in extrinsic policies; rather, the legal concept of causation will serve its grading function only if the concept names some factual state of affairs that determines moral blameworthiness. By ignoring this dominant function of causation in criminal law, the explicit policy tests constructed an artificial concept of legal cause unusable in any just punishment scheme.

This problem does not infect the foreseeability and harm-within-the-risk tests. For those tests do seek to describe a factual state of affairs that plausibly determines moral blameworthiness. They are thus serving the dominant policy that must be served by the concept of causation in the criminal law. Their novelty lies in their reallocation of the locus of blame. On these theories, ‘‘legal cause’’ is not a refinement of an admitted desert-determiner, true causation; it is rather a refinement of another admitted desertdeterminer, namely, mens rea (or ‘‘culpability’’).

Precisely because it is a culpability test, however, the foreseeability test becomes subject to another policy-based objection, that of redundancy. Why should we ask two culpability questions in determining blameworthiness? After we have satisfied ourselves that a defendant is culpable—either because she intended or foresaw some harm, or because she was unreasonable in not foreseeing some harm, given the degree of that harm’s seriousness, the magnitude of its risk, and the lack of justification for taking such a risk—the foreseeability test bids us to ask, ‘‘was the harm foreseeable?’’ This is redundant, because any harm intended or foreseen is foreseeable, and any harm foreseeable enough to render an actor unreasonable for not foreseeing it, is also foreseeable.

The only way the foreseeability test avoids redundancy is by moving toward the harmwithin-the-risk test. That is, one might say that the defendant was culpable in intending, foreseeing, or risking some harm type H, but that what his act in fact caused was an instance of harm type J; the foreseeability test of legal cause becomes nonredundant the moment one restricts it to asking whether J was foreseeable, a different question than the one asked and answered as a matter of mens rea about H. Yet this is to do the work of the harm-within-the-risk test, namely, the work of solving the ‘‘fit problem’’ of mens rea. Moreover, it is to do such work badly. Foreseeability is not the right question to ask in order to fit the harm in fact caused by a defendant to the type of harm he either intended to achieve or foresaw that he would cause. If the foreseeability test is to be restricted to this nonredundant work it is better abandoned for the harm-withinthe-risk test.

The main problem for the harm-within-therisk test itself does not lie in any of the directions we have just explored. The test is in the service of the right policy in its seeking of a true desertdeterminer, and the test does not ask a redundant question. To grade culpability by the mental states of intention, foresight, and risk we have to solve the fit problem above described. The real question for the harm-within-the-risk test is whether this grading by culpable mental states is all that is or should be going on under the rubric of ‘‘legal cause.’’

Consider in this regard two well-known sorts of legal cause cases. It is a time honored maxim of criminal law (as well as tort law) that ‘‘you take your victim as you find him.’’ Standard translation: no matter how abnormal may be the victim’s susceptibilities to injury, and no matter how unforeseeable such injuries may therefore be, a defendant is held to legally cause such injuries. Hit the proverbial thin-skulled man or cut the proverbial hemophiliac, and you have legally caused their deaths. This is hard to square with the harm-within-the-risk test. A defendant who intends to hit or to cut does not necessarily (or even usually) intend to kill. A defendant who foresees that his acts will cause the victim to be struck or cut, does not necessarily (or even usually) foresee that the victim will die. A defendant who negligently risks that his acts will cause a victim to be struck or cut is not necessarily (or even usually) negligent because he also risked death.

The second sort of case involves what are often called ‘‘intervening’’ or ‘‘superseding’’ causes. Suppose the defendant sets explosives next to a prison wall intending to blow up the wall and to get certain inmates out. He foresees to a practical certainty that the explosion will kill the guard on the other side of the wall. He lights the fuse to the bomb and leaves. As it happens, the fuse goes out. However: a stranger passes by the wall, sees the bomb, and relights the fuse for the pleasure of seeing an explosion; or, a thief comes by, sees the bomb and tries to steal it, dropping it in the process and thereby exploding it; or, lightning hits the fuse, reigniting it, and setting off the bomb; and so on. In all variations, the guard on the other side of the wall is killed by the blast. Standard doctrines of intervening causation hold that the defendant did not legally cause the death of the guard (Hart and Honore, 1985, pp. 133–185, 325–362). Yet this is hard to square with the harm-within-the-risk test. After all, did not the defendant foresee just the type of harm an instance of which did occur? Because the harm-within-the-risk question asks a simple type-to-token question—was the particular harm that happened an instance of the type of harm whose foresight by the defendant made him culpable—the test is blind to freakishness of causal route.

The American Law Institute’s Model Penal Code modifies its adoption of the harm-withinthe-risk test in section 2.03 by denying liability for a harm within the risk that is ‘‘too remote or accidental in its occurrence to have a [just] bearing on the actor’s liability or on the gravity of his offense.’’ Such a caveat is an explicit recognition of the inability of the harm-within-the-risk test to accommodate the issues commonly adjudicated as intervening cause issues.

Such a recognition is not nearly broad enough to cover the inadequacy of the harmwithin-the-risk approach. The basic problem with the test is that it ignores all of the issues traditionally adjudicated under the concept of legal cause. Not only is the test blind to freakishiness of causal route in the intervening cause situations, and to the distinction between antecedent versus after-arising abnormalities so crucial to resolution of the thin-skulled-man kind of issue, but the test also ignores all those issues of remoteness meant to be captured by Sir Francis Bacon’s coinage, ‘‘proximate causation.’’ Even where there is no sudden ‘‘break’’ in the chain of causation as in the intervening cause cases, there is a strong sense that causation peters out over space and time (Moore, 1999). Caesar’s crossing the Rubicon may well be a necessary condition for my writing this article, but so many other events have also contributed that Caesar’s causal responsibility has long since petered out. The logical relationship at the heart of the harmwithin-the-risk test—‘‘was the particular harm that happened an instance of the type of harm whose risk, foresight, or intention made the defendant culpable?’’—is incapable of capturing this sensitivity to remoteness. As such, the harmwithin-the-risk test is blind to the basic issue adjudicated under ‘‘legal cause.’’ The harm-withinthe-risk test asks a good question, but it asks it in the wrong place.

Less Conventional Approaches to Causation in The Criminal Law

The problems with the conventional analysis of causation have tempted many to abandon the conventional analysis, root and branch. This generates a search for a unitary notion of causation that is much more discriminating (in what it allows as a cause) than the hopelessly promiscuous counterfactual cause-in-fact test of the conventional analysis. Indeed, the search is for a unitary concept of causation that is so discriminating that it can do the work that on the conventional analysis is done by both cause-in-fact and legal cause doctrines. It is far from obvious that causation is in fact a sufficiently discriminating relation that it can do this much work in assigning responsibility. Nonetheless, there are four such proposals in the academic literature, each having some doctrinal support in the criminal law.

Space Time Proximateness and The Substantial Factor Test

The oldest of the proposals conceives of causation as a metaphysical primitive. Causation is not reducible to any other sort of thing or things, and thus there is little by way of an analysis that one can say about it. However, the one thing we can say is that the causal relation is a scalar relation, which is to say, a matter of degree. One thing can be more of a cause of a certain event than another thing. Moreover, the causal relation diminishes over the number of events through which it is transmitted. The causal relation is thus not a fully transitive relation, in that if event c causes e, and e causes f, and f causes g, it may still be the case that c does not cause g.

On this view of causation, all the law need do is draw the line for liability somewhere on the scale of causal contribution. On matters that vary on a smooth continuum, it is notoriously arbitrary to pick a precise break-point; where is the line between middle age and old age, red and pink, bald and not-bald, or caused and not caused? This approach thus picks an appropriately vague line below which one’s causal contribution to a given harm will be ignored for purposes of assessing responsibility. Let the defendant be responsible and liable for some harm only when the degree of his causal contribution to that harm has reached some non-de minimus, or ‘‘substantial,’’ magnitude. This is the ‘‘substantial factor’’ test, first explicitly articulated by Jeremiah Smith (1911) and then adopted (but only as a test of cause in fact, not of causation generally) by the American Law Institute in its Restatement of Torts. To the common objection that the test tells us little, its defenders reply that that is a virtue, not a vice, for there is little to be said about causation. It, like obscenity, is something we can ‘‘know when we see it,’’ without need of general definitions and tests.

Force, Energy, and The Mechanistic Conception of Cause

Other theorists have thought that we can say more about the nature of the causal relation than that it is scalar and diminishes over intervening events. On this view the nature of causation is to be found in the mechanistic concepts of physics: matter in motion, energy, force (Beale; Epstein; Moore, 1999). This test is similar to the substantial factor view in its conceiving the causal relation to be scalar and of limited transitivity.

This view handles easily the overdetermination cases that are such a problem for the conventional analysis. When two fires join, two bullets strike simultaneously, two motorcycles scare the same horse, each is a cause of the harm because each is doing its physical work. When one nonmortal wound is inflicted together with a larger, mortal wound, the victim dying of loss of blood, each is a cause of death because each did some of the physical work (loss of blood) leading to death.

Such a mechanistic conception of causation is mostly a suggestion in the academic literature because of the elusive and seemingly mysterious use of ‘‘energy’’ and ‘‘force’’ by legal theorists. One suspects some such view is often applied by jurors, but unless theorists can spell out the general nature of the relation being intuitively applied by jurors (as is attempted in Fair), this test tends to collapse to the metaphysically sparer substantial factor test.

Aspect Causation and The Revised Counterfactural Test

There is an ambiguity about causation that we have hitherto ignored but which does find intuitive expression in the decided cases. The ambiguity lies in the sorts of things that can be causes and effects, what are called the ‘‘relata’’ of the causal relation. The usual assumption is that causal relata are whole events; in the phrase ‘‘the firing of his gun caused the death of the victim,’’ the descriptions ‘‘the firing of his gun’’ and ‘‘the death of the victim’’ each name events. Sometimes, however, we might say, ‘‘it was the fact that the gun fired was of such large caliber that caused the victim to die.’’ That it was a large-caliber-gun firing is an aspect of the event. The whole event was the firing of the gun; one of that event’s properties was that it was a large-caliber-gun firing.

Lawyers adopt this shift in causal relata when they distinguish the defendant’s action as a cause, from some wrongful aspect of the defendant’s action which is not causally relevant. Thus, when an unlicensed driver injuries a pedestrian, they say: ‘‘while the driving did cause the injuries, the fact that it was unlicensed driving did not.’’

A restrictive notion of causation can be found by restricting things eligible to be causal relata to aspects of a defendant’s action that make him culpable (either by foresight, intent, or risk). Typically, this restriction is married to some counterfactual conception of causation (Wright, 1985). The resulting conception of causation promises fully as discriminating a notion as was achieved by the harm-within-the-risk approach of the conventional analysis (for notice that this conception really is just harm-within-the-risk conceptualized as a true causal doctrine rather than a construction of legal policy). Such a conception of causation must thus face the challenges faced by the harm-within-the-risk conception, namely, the inadequacy of either analysis to deal with intervening causation, remoteness, freakishness of causal route, and so on. In addition, this proposed conception faces metaphysical hurdles not faced by the harmwithin-the-risk analysis, for it must make sense of the idea of aspects of events being causes, rather than events themselves.

Hart and Honore’s Direct Cause Test

Beginning in a series of articles in the 1950s and culminating in their massive book, Causation in the Law (1959), Herbert Hart and Tony Honore sought to describe a unitary conception of causation they saw as implicit both in the law and in everyday usages of the concept. One can see their concept most easily in three steps. First, begin with some version of the counterfactual analysis: a cause is a necessary condition for its effect (or perhaps a NESS condition). Second, a cause is not any necessary condition; rather, out of the plethora of conditions necessary for the happening of any event, only two sorts are eligible to be causes. Free, informed, voluntary human actions, and those abnormal conjunctions of natural events we colloquially refer to as ‘‘coincidences,’’ are the two kind of necessary conditions we find salient and honor as ‘‘causes’’ (versus mere ‘‘background conditions’’). Third, such voluntary human action and abnormal natural events cause a given effect only if some other voluntary human action or abnormal natural event does not intervene between the first such event and its putative effect. Such salient events, in other words, are breakers of causal chains as much as they are initiators of causal chains, so that if they do intervene they relegate all earlier such events to the status of mere background conditions.

Hart and Honore built on considerable case law support for their two candidates for intervening causes (Carpenter, pp. 471–530). Indeed, it is arguable that the basic distinction between principal and accomplice liability depends in part on this conceptualization of causation (Kadish). One concern for this view of causation, nonetheless, is the worry that it is incomplete with respect to the remoteness range of issues usually dealt with under the rubric of ‘‘legal cause’’ in the law. Causation fades out gradually as much as it breaks off suddenly in the law, and the Hart and Honore analysis ignores this.

Bibliography:

1. American Law Institute. Model Penal Code: Proposed Official Draft. Philadelphia: American Law Institute, 1962.
2. American Law Institute. Model Penal Code and Commentaries. Philadelphia: American Law Institute, 1985.
3. BEALE, JOSEPH. ‘‘The Proximate Consequences of an Act.’’ Harvard Law Review 33 (1920): 633– 658.
4. BUXTON, R. ‘‘Circumstances, Consequences, and Attempted Rape.’’ Criminal Law Review (1984): 25–34.
5. CARPENTER, CHARLES. ‘‘Workable Rules for Determining Proximate Cause.’’ California Law Review 20 (1932): 229–259, 396–419, 471–539.
6. EDGARTON, HENRY. ‘‘Legal Cause.’’ University of Pennsylvania Law Review 72 (1924): 211–244, 343–376.
7. EPSTEIN, RICHARD. ‘‘A Theory of Strict Liability.’’ Journal of Legal Studies 2 (1973): 151–204.
8. FAIR, DAVIS. ‘‘Causation and the Flows of Energy.’’ Erkenntnis (1979): 219–250.
9. FLETCHER, GEORGE. Rethinking Criminal Law. Boston: Little Brown, 1978.
10. FLETCHER, GEORGE. Basic Concepts of Criminal Law. Oxford, U.K.: Oxford University Press, 1998.
11. GREEN, LEON. Rationale of Proximate Cause. Kansas City, Mo.: Vernon Law Book Co., 1927.
12. HART, H. L. A., and HONORE, TONY. Causation in the Law. Oxford, U.K.: Oxford University Press, 1959.
13. KADISH, SANFORD. ‘‘Causation and Complicity: A Study in the Interpretation of Doctrine.’’ California Law Review 73 (1985): 323–410.
14. LEWIS, DAVID. ‘‘Causation.’’ Journal of Philosophy 70 (1973): 556–567.
15. MACKIE, JOHN. The Cement of the Universe. Oxford, U.K.: Oxford University Press, 1974.
16. MILL, J. S. A System of Logic, 8th ed. London: Longman, 1961.
17. MOORE, MICHAEL. Act and Crime: The Implications of the Philosophy of Action for the Criminal Law. Oxford, U.K.: Clarendon Press, 1993.
18. MOORE, MICHAEL. Placing Blame: A General Theory of the Criminal Law. Oxford, U.K.: Oxford University Press, 1997.
19. MOORE, MICHAEL. ‘‘Causation and Responsibility.’’ Social Philosophy and Policy 16 (1999): 1–51.
20. SMITH, JEREMIAH. ‘‘Legal Cause in Actions of Tort.’’ Harvard Law Review 25 (1911): 103– 128, 223–252, 253–269, 303–321.
21. WILLIAMS, GLANVILLE. ‘‘The Problem of Reckless Attempts.’’ Criminal Law Review (1983): 365– 375.
22. WRIGHT, RICHARD. ‘‘Causation in Tort Law.’’ California Law Review 73 (1985): 1737–1828.
23. WRIGHT, RICHARD. ‘‘Causation, Responsibility, Risk, Probability, Naked Statistics, and Proof: Pruning the Bramble Bush by Clarifying the Concepts.’’ Iowa Law Review 73 (1988): 1001–1077.