R. v. Maybin, 2012 SCC 24, just released, is an important decision dealing with causation in manslaughter and when an intervening act may be seen to absolve liability.
Courts have used a number of analytical approaches to determine when an intervening act absolves the accused of legal responsibility for manslaughter. For example, both the “reasonable foreseeability” and the “intentional, independent act” approach may be useful in assessing legal causation depending on the specific factual matrix. These approaches grapple with the issue of the moral connection between the accused’s acts and the death; they acknowledge that an intervening act that is reasonably foreseeable to the accused may well not break the chain of causation, and that an independent and intentional act by a third party may in some cases make it unfair to hold the accused responsible. These approaches may be useful tools depending upon the factual context. However, the analysis must focus on first principles and recognize that these tools are analytical aids and do not alter the standard of legal causation or substitute new tests. Even in cases where it is alleged that an intervening act has interrupted the chain of legal causation, the causation test remains whether the dangerous and unlawful acts of the accused are a significant contributing cause of the victim’s death.
The reasonable foreseeability approach questions whether it is fair to attribute the resulting death to the initial actor and posits that an accused who undertakes a dangerous act, and in so doing contributes to a death, should bear the risk that other foreseeable acts may intervene and contribute to that death. The time to assess reasonable foreseeability is at the time of the initial unlawful act, rather than at the time of the intervening act as it is too restrictive to require that the precise details of the event be objectively foreseeable. It is the general nature of the intervening acts and the accompanying risk of harm that needs to be reasonably foreseeable. The intervening acts and the ensuing non-trivial harm must be reasonably foreseeable in the sense that the acts and the harm that actually transpired flowed reasonably from the conduct of the accused. If so, then the accused’s actions may remain a significant contributing cause of death.
Whether an intervening act is independent is sometimes framed as a question of whether the intervening act is a response to the acts of the accused. In other words, did the act of the accused merely set the scene, allowing other circumstances to (coincidentally) intervene, or did the act of the accused trigger or provoke the action of the intervening party? If the intervening act is a direct response or is directly linked to the accused’s actions, and does not by its nature overwhelm the original actions, then the accused cannot be said to be morally innocent of the death.
The Court holds:
 The causal link between an accused’s actions and the victim’s death is not always obvious in homicide cases. In cases involving multiple causes of death or intervening causes between an accused’s action and the victim’s death, determining causation is more challenging. An accused’s unlawful actions need not be the only cause of death, or even the direct cause of death; the court must determine if the accused’s actions are a significant contributing cause of death.
2. General Principles of Causation for Manslaughter
 Section 222(1) of the Criminal Code, R.S.C. 1985, c. C-46, provides that “[a] person commits homicide when, directly or indirectly, by any means, he causes the death of a human being.” Subsection (5) provides that “[a] person commits culpable homicide when he causes the death of a human being, (a) by means of an unlawful act”. The Criminal Code also identifies some circumstances in which the chain of causation will not be broken: a person causes the death of a human being notwithstanding (a) that death might have been prevented by resorting to proper means (s. 224) or (b) that the immediate cause of death is proper or improper treatment applied in good faith (s. 225).
 In Smithers, this Court pronounced the test for causation in manslaughter as “a contributing cause of death, outside the de minimis range” (p. 519). In that case, the accused punched the victim in the head and delivered a hard, fast kick to the victim’s stomach. The medical cause of the victim’s death was the aspiration of foreign materials present from vomiting; doctors testified that such aspiration rarely happens when the epiglottis functions properly. Dickson J. stated that it was “immaterial that the death was in part caused by a malfunctioning epiglottis to which malfunction the [accused] may, or may not, have contributed” (p. 519). An unlawful act may remain a legal cause of a person’s death even if the unlawful act, by itself, would not have caused that person’s death, provided it contributed beyond de minimis to that death (p. 522). The Court thus recognized that there may be a number of contributing causes of death.
 In Nette, this Court affirmed the validity of the de minimis causation standard expressed in Smithers for culpable homicide. Writing for the majority, Arbour J. noted that causation in homicide cases involves two aspects: factual and legal causation. Factual causation is “an inquiry about how the victim came to his or her death, in a medical, mechanical, or physical sense, and with the contribution of the accused to that result” (Nette, at para. 44). The trier of fact usually asks: “But for” the action(s) of the accused, would the death have occurred? Factual causation is therefore inclusive in scope.
 Legal causation, however, is a narrowing concept which funnels a wider range of factual causes into those which are sufficiently connected to a harm to warrant legal responsibility. Arbour J. noted that legal causation is “based on concepts of moral responsibility and is not a mechanical or mathematical exercise” (Nette, at para. 83). She stated, at para. 45:
Legal causation, which is also referred to as imputable causation, is concerned with the question of whether the accused person should be held responsible in law for the death that occurred. It is informed by legal considerations such as the wording of the section creating the offence and principles of interpretation. These legal considerations, in turn, reflect fundamental principles of criminal justice such as the principle that the morally innocent should not be punished . . . .
4. Legal Causation ― Intervening Act
 The doctrine of intervening acts is used, when relevant, for the purpose of reducing the scope of acts which generate criminal liability. As Cromwell J.A. stated in R. v. Tower, 2008 NSCA 3, 261 N.S.R. (2d) 135, “the law recognizes that other causes may intervene to ‘break the chain of causation’ between the accused’s acts and the death. This is the concept of an ‘intervening cause’, that some new event or events result in the accused’s actions not being a significant contributing cause of death” (para. 25).
 Jurisprudence in
Several efforts . . . may be gleaned from the case authorities. They include statements to the effect that a defendant is relieved of causal blame if the intervening event was “abnormal”, “an unreasonable act”, a “coincidence”, “not a natural consequence”, comprised the “voluntary conduct of the intervener” or “was not reasonably foreseeable”.
(“Blamable Causation” (2000), 24 Crim.L.J. 144, at p. 151)
 The first approach, applied by the majority, looks to whether the intervening act was objectively or reasonably foreseeable (see R. v. Shilon (2006), 240 C.C.C. (3d) 401 (Ont.
 The second approach, applied by the dissent, considers whether the intervening act is an independent factor that severs the impact of the accused’s actions, making the intervening act, in law, the sole cause of the victim’s death (see R. v. Pagett (1983), 76 Cr. App. R. 279 (C.A.); R. v. Smith,  2 Q.B. 35 (C.-M.A.C.)). The dissent held that the bouncer’s assault was just such an independent factor.
 In my view, both these approaches are analytical aids ― not new standards of legal causation. I agree with the intervener, the Attorney General of Ontario, that while such approaches may be helpful, they do not create new tests that are dispositive. Neither an unforeseeable intervening act nor an independent intervening act is necessarily a sufficient condition to break the chain of legal causation. Similarly, the fact that the intervening act was reasonably foreseeable, or was not an independent act, is not necessarily a sufficient condition to establish legal causation. Even in cases where it is alleged that an intervening act has interrupted the chain of legal causation, the causation test articulated in Smithers and confirmed in Nette remains the same: Were the dangerous, unlawful acts of the accused a significant contributing cause of the victim’s death?
 Depending on the circumstances, assessments of foreseeability or independence may be more or less helpful in determining whether an accused’s unlawful acts were still a significant contributing cause at the time of death. Any assessment of legal causation should maintain focus on whether the accused should be held legally responsible for the consequences of his actions, or whether holding the accused responsible for the death would amount to punishing a moral innocent.
5. Reasonable Foreseeability
 An intervening act that is reasonably foreseeable will usually not break or rupture the chain of causation so as to relieve the offender of legal responsibility for the unintended result. This approach posits that an accused who undertakes a dangerous act, and in so doing contributes to a death, should bear the risk that other foreseeable acts may intervene and contribute to that death. Because the issue is whether the actions and consequences were reasonably foreseeable prospectively, at the time of the accused’s objectively dangerous and unlawful act, it accords with our notions of moral accountability. This approach addresses the question: Is it fair to attribute the resulting death to the initial actor?
 Courts have sometimes couched the principle of foreseeability in different terms, asking whether the intervening act is so “extraordinary” or “unusual” that the accused should not be held responsible for the consequences of that act. In R. v. Sinclair, 2009 MBCA 71, 240
 Objective foreseeability has thus been a useful tool in determining whether an intervening act severs the chain of legal causation. The more difficult question in applying such an approach is the scope of what has to be reasonably foreseeable. In this case, the parties disagree about whether the intervening act ― the blow delivered by the bouncer ― was reasonably foreseeable. While both the majority and dissent opinions apply a reasonable foreseeability framework, they arrive at different conclusions. This result is driven by their different views regarding what precisely must be reasonably foreseeable. Is it the specific assault by the intervening actor? Is it simply the risk of further bodily harm? Or is it the general nature of intervening acts and the accompanying risk of harm?
 For these reasons, I conclude that it is the general nature of the intervening acts and the accompanying risk of harm that needs to be reasonably foreseeable. Legal causation does not require that the accused must objectively foresee the precise future consequences of their conduct. Nor does it assist in addressing moral culpability to require merely that the risk of some non-trivial bodily harm is reasonably foreseeable. Rather, the intervening acts and the ensuing non-trivial harm must be reasonably foreseeable in the sense that the acts and the harm that actually transpired flowed reasonably from the conduct of the appellants. If so, then the accused’s actions may remain a significant contributing cause of death.
 One final point on this issue. The majority of the Court of Appeal stated that the reasonable foreseeability test is determinative on the issue of legal causation (para. 35):
. . . the law will not hold someone legally responsible if the ordinarily circumspect person would not have seen the outcome as likely to result from his or her act. In my view, this principle explains the purpose of the novus actus interveniens rule. The application of the rule provides a way of ensuring that a person will not be held responsible for objectively unforeseeable consequences.
 The Court of Appeal in effect elevated this analytical approach to a new causation rule. I do not agree. The reasonable foreseeability approach is a useful tool and directly incorporates the notion of blameworthiness. However, as noted above, there may be other helpful analytical tools to assess whether legal responsibility should be imputed to the accused and whether the accused’s acts were a significant contributing cause of death as required in Smithers and Nette.
6. Independent Acts
 In dissent, Finch C.J.B.C. agreed that “a person should not be held responsible for objectively unforeseeable consequences” and concluded that the actions of the bouncer were not reasonably foreseeable. He continued:
However, persons should similarly not be held responsible for intentional actions of a third party acting independently. This was articulated by the Ontario Court of Appeal in R v. J.S.R. (2008), 239 O.A.C. 42; 2008 ONCA 544, at para. 31:
[D]espite the existence of factual causation, it is said to be unfair to impute legal liability for the death to a person whose actions have been effectively overtaken by the more immediate causal action of another party acting independently . . .
. . .
[The bouncer’s] intentional conduct in striking the unconscious [victim] constitutes an intervening act in this case. He is an independent third party and the Maybin brothers should not be held morally or legally responsible for his acts, in the absence of a conclusion that the blows of Timothy Maybin and [the bouncer] in conjunction were the cause of death. [Emphasis in original; paras. 72-73.]
 Whether the effects of an accused’s actions are “effectively overtaken by the more immediate causal action of another party acting independently” involves an assessment of the relative weight of the causes, looking retrospectively from the death.
 Courts have sought to articulate when the first cause ought to be overlooked because of the nature and effect of the subsequent causes, quite apart from whether or not the subsequent causes may have been foreseeable. In R. v. Smith, the victim died in hospital after being stabbed by the accused. It was later discovered that the victim had been improperly treated. When deciding whether the actions of medical staff constituted an intervening cause, the English Courts Martial Appeal Court declared that an intervening cause shields the accused from responsibility only if the accused’s act is “merely the setting in which another cause operates” (p. 43). Or, put another way, only if the intervening cause “is so overwhelming as to make the original wound merely part of the history” leading to the victim’s death (p. 43). Ultimately, the court articulated the standard as: “. . . if at the time of death the original wound is still an operating cause and a substantial cause, then the death can properly be said to be the result of the wound”(pp. 42-43). In R. v. Hallett when faced with the death of a man left unconscious on a beach who drowned as a result of “the ordinary operations of the tides” (p. 150), the court asked whether the original unlawful act was “so connected with the event that it . . . must be regarded as having a sufficiently substantial causal effect which subsisted up to the happening of the event” (p. 149).
 In R. v. Shilon, the Ontario Court of Appeal accepted that “independent voluntary human intervention in events started by an accused may break the chain of causation” but concluded that it was the accused who “created and continued the highly charged situation” and “provoked” the third party’s dangerous driving, which was therefore “directly linked” to the accused’s actions (para. 43).
 Whether an intervening act is independent is thus sometimes framed as a question of whether the intervening act is a response to the acts of the accused. In other words, did the act of the accused merely set the scene, allowing other circumstances to (coincidentally) intervene, or did the act of the accused trigger or provoke the action of the intervening party?
 When the intervening acts are natural events, they are more closely tied to the theory of foreseeability, and the courts ask whether the event was “extraordinary”, as in R. v. Hallett. When the intervening acts are those of a person, exercising his or her free will, the focus is often on the independence of the actions.
 The academic community has also sought to explain when the actions of another person will interrupt the chain of causation. Glanville Williams argues that while people are subject to the “causes” of nature, they have control over their actions and a voluntary act starts a new chain of causation, regardless of what has happened before. He explains how this accords with our ideas of moral responsibility and just punishment:
The first actor who starts on a dangerous or criminal plan will often be responsible for what happens if no one else intervenes; but a subsequent actor who has reached responsible years, is of sound mind, has full knowledge of what he is doing, and is not acting under intimidation or other pressure or stress resulting from the defendant’s conduct, replaces him as the responsible actor. Such an intervening act is thought to break the moral connection that would otherwise have been perceived between the defendant’s acts and the forbidden consequence.
(“Finis for Novus Actus?” (1989), 48
 An intervening act by another person does not always sever the causal connection between the accused’s act and the result: as mentioned, ss. 224 and 225 of the Criminal Code provide that the chain of causation is not broken if death could otherwise have been prevented by resorting to proper means (s. 224), or if the immediate cause of death is proper or improper treatment that is applied in good faith (s. 225). In addition, in this case, I need not consider the actions of a third party who acts in good faith, or under mistake, intimidation or similar pressure, or whose actions are not voluntary. Here, the bouncer criminally assaulted the unconscious victim causing bodily harm.
 I agree with the respondent that the inquiry as to whether an intervening act is independent is distinct from the inquiry of whether the accused and the intervening actor are parties acting in concert or with common purpose pursuant to s. 21 of the Criminal Code. If they are parties, each is responsible for the acts of the other. In the legal causation analysis, their respective acts remain separate. Legal causation focusses on the connection (or independence) between the actions of the individuals and the effect of those actions, not on the connection between the actors.
 Thus, the finding by the trial judge of independence for the purposes of accessorial liability under s. 21 would not affect a finding that the actions of the appellants triggered or provoked the actions of the intervening actor. Similarly, the fact that the bouncer was an independent third party does not, as suggested in the dissent, end the legal causation analysis. Their respective actions must be sufficiently independent for legal causation purposes.
 Courts have used a number of analytical approaches to determine when an intervening act absolves the accused of legal responsibility for manslaughter. These approaches grapple with the issue of the moral connection between the accused’s acts and the death; they acknowledge that an intervening act that is reasonably foreseeable to the accused may well not break the chain of causation, and that an independent and intentional act by a third party may in some cases make it unfair to hold the accused responsible. In my view, these approaches may be useful tools depending upon the factual context. However, the analysis must focus on first principles and recognize that these tools do not alter the standard of causation or substitute new tests. The dangerous and unlawful acts of the accused must be a significant contributing cause of the victim’s death.