(concurring separately):
I join in affirming the defendant’s convictions of second degree murder. Although I submit that it would have been preferable for the trial judge to give an instruction on unanimity as to the defendant’s mens rea, I do not believe the fundamental principle of jury unanimity was violated in this case. I write separately, however, to emphasize that in a different context, when a jury is allowed to convict on the basis of alternative mental states without requiring juror unanimity, a constitutional violation might well occur.
I.
The jury instruction given in this case, which tracked U.C.A., 1953, § 76-5-203 (1978 ed.), the second degree murder statute, permitted the jury to return a verdict of guilty even though the jurors were not unanimous as to the mental state of the *170defendant.1 Thus, the instruction described three possible alternative mental states which would suffice for a guilty verdict. Because those mental states are so highly similar, from the point of view of mental functioning and culpability, I think the jury was for essential constitutional purposes unanimous on the mens rea element.
Nevertheless, I fear that a broad application of the Sullivan rule, which the Court adopts, will result in a violation of the Utah constitutional requirement of jury unanimity if a criminal conviction is allowed on proof of alternative mental states which are not essentially the same either in nature or degree of culpability.2 To hold that a jury need only agree on the act committed but need not agree on the actor’s mental state ignores the importance of a defendant’s mental state as a determinant of culpability under the Utah Criminal Code and traditional principles of criminal responsibility. The homicide statutes, in particular, make the culpability of a defendant turn on his mental state at the time of the killing.
Subtle, but important, distinctions exist between mental states that lie side by side along the continuum of various mental states. If unanimity as to a mental state is not required, jurors may forego a thorough analysis of the defendant’s mental state and of possible lesser included offenses. The difference between depraved indifference murder, which is one form of second degree murder, and reckless manslaughter, which is a lesser crime, is so subtle that under different facts, I would think it *171would be error not to give a jury instruction on unanimity on the second degree murder charge.
II.
The Due Process Clause protects the accused against conviction “except upon proof beyond a reasonable doubt of every fact necessary to constitute the crime with which he is charged.” In re Winship, 397 U.S. 358, 364, 90 S.Ct. 1068, 1073, 25 L.Ed.2d 368 (1970). Stronger proof is required in criminal cases than in civil cases in order to reduce the inevitable margin of error in fact-finding. Id. at 363, 90 S.Ct. at 1072. The unanimous jury requirement, like the reasonable doubt standard, also “impresses on the trier of fact the necessity of reaching a subjective state of certitude on the facts in issue.” Id. at 364, 90 S.Ct. at 1072. Article I, section 10 of the Utah Constitution, which states, “[I]n criminal cases the verdict shall be unanimous [but] [i]n civil cases three-fourths of the jurors may find a verdict,” suggests that the certitude of unanimous jury verdicts in criminal cases was fundamentally important to our Constitution’s framers.
Because due process requires that each essential element of a crime be proved beyond a reasonable doubt, fundamental fairness also requires jurors to agree unanimously on each essential element, including the requisite type of mens rea. The critical question is, “How far up the trunk and branches of the evidence tree must this unanimity extend?” State v. Rasmussen, 92 Utah 357, 376, 68 P.2d 176, 185 (1937) (Wolfe, J., concurring in the result). Clearly, unanimity is not required on each evi-dentiary point, but it is required, in my view, as to both the ultimate criminal act committed and the defendant’s state of mind.
The verdict in this case was essentially unanimous because all of the mental states in § 76-5-2033 which were submitted to the jury are forms of common law malice aforethought and because, given the facts of the case, it is unreasonable to suppose the defendant acted with a lesser mental state.
In convicting the defendant of second degree murder under either § 76-5-203(l)(a), (b), or (c), each juror found beyond a reasonable doubt that the defendant either (1) intentionally caused the death of the victims; (2) intended to cause serious bodily injury to the victims and committed an act clearly dangerous to human life; or (3) acted with a depraved indifference to human life and knew that his conduct created a grave risk of death.
These definitions of second degree murder and the definitions in the Model Penal Code (from which the Utah Code’s murder provision is derived in substantial part) are statutory definitions of the various mental states which at common law constituted malice aforethought. Model Penal Code Commentary, art. 210, § 210.2 comments 1 & 2, at 13-19 (1980) (“MPC Commentary”); U.C.A., 1953, § 76-5-203 (1978 ed.); U.C.A., 1953, § 76-30-1, -2, -3 (1953 ed.) (repealed 1973).
Prior to 1973, murder in Utah was defined as “the unlawful killing of a human being with malice aforethought.” U.C.A., 1953, § 76-30-1 (1953 ed.) (repealed 1973). *172In State v. Russell, 106 Utah 116, 146 P.2d 1003 (1944), the Court defined the intent necessary to constitute malice aforethought:
In order to have the necessary malice to commit murder (not necessarily murder in the first degree), the killing must be unlawful, it must result from or be caused by an act or omission to act committed with one of the following intentions: (1) an intention or design previously formed to kill or cause great bodily injury; or (2) an intention or design previously formed to do an act or omit to do an act, knowing that the reasonable and natural consequences thereof would be likely to cause death or great bodily injury; or (3) a previously thought out intentional or designed perpetration or attempt to perpetrate one of certain kinds of felonies.
Id. at 126, 145 P.2d at 1007 (emphasis in original). Similarly, the MPC Commentary summarizes the common law concept of malice aforethought as follows:
At common law, murder was defined as the unlawful killing of another human being with “malice aforethought.” Whatever the original meaning of that phrase, it became over time an “arbitrary symbol” used by judges to signify any of a number of mental states deemed sufficient to support liability for murder. Successive generations added new content to “malice aforethought” until it encompassed a variety of mental attitudes bearing no predictable relation to the ordinary sense of the two words....
Various authorities have given different summaries of the several meanings of “malice aforethought.” Generally, these definitions converge on four constituent states of mind. First and foremost, there was intent to kill. Common-law authorities included in the notion of intent to kill awareness that the death of another would result from one’s actions, even if the actor had no particular desire to achieve such a consequence. Thus, intentional or knowing homicide was murder unless the actor killed in the heat of passion engendered by adequate provocation, in which case the crime was manslaughter. A second species of murder involved intent to cause grievous bodily harm. Again, knowledge that conduct would cause serious bodily injury was generally assimilated to intent and was deemed sufficient for murder if death of another actually resulted. A third category of murder was sometimes called depraved-heart murder. This label derived from decisions and statutes condemning as murder unintentional homicide under circumstances eyincing a “depraved mind” or an “abandoned and malignant heart.” Older authorities may have described such circumstances as giving rise to an “implied” or “presumed” intent to kill or injure, but the essential concept was one of extreme recklessness regarding homicidal risk. Thus, a person might be liable for murder absent any actual intent to kill or injure if he caused the death of another in a manner exhibiting a “wanton and wilful disregard of an unreasonable human risk” or, in confusing elaboration, a “wickedness of disposition, hardness of heart, cruelty, recklessness of consequences, and a mind regardless of social duty.” The fourth kind of murder was based on intent to commit a felony. This is the origin of the felony-murder rule, which assigns strict liability for homicide committed during the commission of a felony. These four states of mind exhausted the meaning of a “malice aforethought”; the phrase had no residual content.
MPC Commentary, Art. 210, § 210.2 comment 1, at 13-15 (1980) (emphasis added) (footnotes omitted).
The MPC attempted to clarify, modify, and codify the mental states and circumstances under which homicide is considered murder. The MPC defines murder as follows:
§ 210.2 Murder
(1) Except as provided in Section 210.-3(l)(b), criminal homicide constitutes murder when:
*173(a) it is committed purposely or knowingly; or
(b) it is committed recklessly under circumstances manifesting extreme indifference to the value of human life. Such recklessness and indifference are presumed if the actor is engaged or is an accomplice in the commission of, or an attempt to commit, or flight after committing or attempting to commit robbery, rape or deviate sexual intercourse by force or threat of force, arson, burglary, kidnapping or felonious escape.
(2) Murder is a felony of the first degree [but a person convicted of murder may be sentenced to death, as provided in Section 210.6].
(Footnote omitted.)
The MPC drafters deleted intent to cause grievous bodily harm “as an independently sufficient culpability for murder [because of] the judgment that it is preferable to handle such cases under the standards of extreme recklessness and recklessness” contained in the MPC’s extreme indifference murder and reckless manslaughter statutes. MPC Commentary, § 210.2 comment 5, at 28-29 (1980). Further, the MPC eliminated “strict liability” felony murder and created instead a presumption that the commission of certain enumerated felonies is an objective circumstance that demonstrates both that the defendant acted recklessly and that his conduct was sufficiently callous to the value of human life that death caused during the commission of one of those felonies was extreme indifference murder, as opposed to manslaughter or some other type of homicide. See MPC Commentary, § 210.2 comment 6, at 29-42 (outlining the reasons for this change).
Although § 76-5-203, supra, note 3, is consistent with the MPC murder statute and the commentary’s discussion of malice aforethought, it clearly contains significant departures. First, the statute retains the common law “intent to cause serious bodily injury” mental state as a separate mental state from depraved indifference murder.
Second, the Legislature departed from the MPC’s formulation of depraved indifference murder. The MPC formulation imposes murder liability if the actor recklessly causes death under circumstances evidencing extreme indifference to human life. MPC § 210.2(l)(b). Section 76-5-203(l)(c) originally defined depraved indifference murder as a homicide committed when the defendant “recklessly engaged in conduct which created a grave risk of death to another” under circumstances evidencing depraved indifference to human life. § 76— 5-203(l)(c) (1978 ed.) (emphasis added). In 1979, the Legislature deleted the word “recklessly” from § 76-5-203, and this Court held that mere reckless conduct was not sufficient to prove the offense of second degree murder. State v. Bindrup, 655 P.2d 674, 676 (Utah 1982). In State v. Fontana, 680 P.2d 1042 (Utah 1984), we held that to be liable under § 76-5-203(l)(c), the defendant roust act knowingly and be aware that his conduct creates a grave risk of death. Id. at 1046.
Finally, the Utah Legislature retained felony murder as a separate category of murder, rather than as a circumstance from which recklessness and depraved indifference can be presumed. § 76-5-203(l)(d).
Despite these departures from the Model Penal Code, it is clear from Russell, 106 Utah 116, 145 P.2d 1003, and the MPC Commentary that all of the mental states in § 76-5-203(l)(a), (b), (c) are essentially forms of common law malice aforethought. Each is at least “an intention or design previously formed to do an act or omit to do an act, knowing that the reasonable and natural consequences thereof would be likely to cause death or great bodily injury.” Russell, 106 Utah at 126, 145 P.2d at 1007.
Not only is each mental state in the Utah statute a form of common law malice aforethought, but each one also amounts to a varied form of depraved indifference murder. Certainly, intentionally causing death demonstrates depraved indifference to the value of the life taken.
*174The significance of purpose or knowledge as a standard of [murder] culpability is that, cases of provocation or other mitigation apart, purposeful or knowing homicide demonstrates precisely such indifference to the value of human life.
MPC Commentary, § 210.2 comment 4, at 21. Therefore, a juror who finds that a defendant intentionally or knowingly committed a homicide must necessarily find depraved indifference because a defendant who intends to kill is aware that his conduct creates a grave risk of death.
A person who intends to cause serious bodily injury while doing an act “clearly dangerous to human life” also acts with a depraved indifference to the value of human life. Serious bodily injury is defined as “bodily injury that creates or causes serious permanent disfigurement, protracted loss or impairment of the function of any bodily member or organ or creates a substantial risk of death.” § 76-1-601(9). A person whose “conscious objective or desire” is to cause that type of injury while committing an act clearly dangerous to human life, § 76-2-103(1), also demonstrates depraved indifference. The objective depraved indifference judgment is made out when the nature of the injury the defendant intends to cause is “serious,” as opposed to “slight.” See MPC Commentary, § 210.2 comment 5, at 28-29 (intent to “cause injury of a particular nature or gravity is, of course, a relevant consideration in determining whether [a defendant] acted with ‘extreme indifference to the value of human life’ ”).
It follows that regardless of which mental state individual jurors relied upon in reaching this verdict, all agreed that the defendant knowingly engaged in conduct that created a grave risk of death to the victims and that he acted under circumstances evidencing a depraved indifference to human life.
Although the jury verdict under § 76-5-203 was essentially logically unanimous, the subsection relating to depraved indifference murder, § 76-5-203(l)(c), could, in cases not clearly evidencing depraved indifference, still present a problem for jurors. Under § 76-2-103(3), a defendant acts “recklessly ... when he is aware of but consciously disregards a substantial and unjustifiable risk that the circumstances exist or that the result will occur.” In other words, engaging in conduct while aware that the conduct creates a substantial and unjustifiable risk is a reckless act that would support a conviction for reckless manslaughter. § 76-5-205(l)(a). This Court reduced a second degree murder conviction to manslaughter in State v. Bindrup, 655 P.2d 674 (Utah 1982), because the evidence showed that the defendant “was aware of the risk occasioned by his conduct and that he consciously chose to disregard it.” Id. at 676.
Murder liability under § 76-5-203(l)(c), on the other hand, attaches when the actor engages in conduct which causes death with “knowledge that [it creates] a grave risk of death to another.” State v. Fontana, 680 P.2d 1042, 1047 (Utah 1984). Causing death while knowingly engaged in conduct which creates a grave risk of death is virtually the same as causing death while “aware of the risk” occasioned by dangerous conduct. Therefore, after Fontana, the only distinction between depraved indifference murder and reckless manslaughter is the additional juror judgment that the magnitude of the risk created by a particular defendant’s conduct objectively evidences the defendant’s depraved indifference to human life. See Development, Depraved Indifference Murder, 1985 Utah L.Rev. 150; Note, State v. Fontana; An Illusory Solution to Utah’s Depraved Indifference Murder Mens Rea Problem, 12 J.Contemp.L. 177, 186-87 (1986). In cases where the facts do not necessarily demonstrate depraved indifference to the value of human life, a jury might not examine carefully reckless manslaughter if some jurors are of the opinion that the defendant acted intentionally, while some think the defendant acted merely with knowledge that his conduct created a grave risk of death. If unanimity were not required, a manslaughter conviction, no matter how viable an *175alternative, would not be seriously considered by the jury.
That problem is not presented here, however, because the facts of this case clearly meet the objective depraved indifference standard. The defendant told Floyd and LaRue, “If I don’t start getting some answers, I am going to start blowing everybody away.” He pointed his gun at Floyd and when Floyd attempted to move it away, he shot Floyd once in the chin. He then ran outside, and when LaRue went back in the house, he shot at her through the window. He also testified that he knew the gun was a dangerous weapon and was aware of the probable result if someone were to shoot another in the face.
In sum, a court should require unanimity as to the mental state when a jury could base a conviction on two or more mental states and a lesser-included offense is a possible alternative conviction depending on the mens rea found by the jury. Careful attention should also be paid in cases involving other crimes where perhaps even more subtle distinctions exist between the alternative mental states and other lesser included mental states. Because of the essential nature of a defendant’s mental state to a finding of culpability, and because of the subtle distinctions between various mental states, fundamental fairness clearly requires unanimity on the issue of the defendant’s mental state.
. Instruction number fourteen read as follows:
Before you can convict the defendant, Dick Roundy Russell, of the crime of Murder in the Second Degree, a lesser included offense of the crime charged in Count I, you must believe from all the evidence and beyond a reasonable doubt each and every one of the following elements of that offense:
1. That on or about the 16th day of May, 1981, in Salt Lake County, State of Utah, Floyd Rowley was killed; and
2. That defendant is the person who caused the death of Floyd Rowley and did so under one of the following circumstances:
a. Defendant intentionally or knowingly caused the death of Floyd Rowley; or
b. Defendant intended, to cause serious bodily injury to Floyd Rowely [sic] and committed an act clearly dangerous to human life that caused the death of Floyd Rowely [sic]; or
c. Defendant acted under circumstance [sic] which evidenced a depraved indifference to human life and engaged in conduct which created a grave risk of death to another and thereby caused the death of Floyd Rowley.
If, after careful consideration of all of the evidence in this case you are not convinced beyond a reasonable doubt of the foregoing elements, then you must find the defendant not guilty of Murder in the Segond [sic] Degree, a lesser included offense of the crime charged in Count I. If you find the defendant not guilty of Murder in the Second Degree under this instruction then you should consider the elements of Manslaughter as set forth in the next instruction.
If, on the other hand, you are convinced of the truth of element number 1 above and any one of the three circumstance [sic] in element number 2 above beyond a reasonable doubt, then you must find the defendant guilty of Murder in the Second Degree a lesser included offense of the crime charged in Count I. A similar instruction was given for the murder of LaRue Rowley.
. State v. James, 698 P.2d 1161 (Alaska 1985) (cited by the majority opinion), presents a clear example of a situation where unanimity is not ensured by merely requiring jury agreement on the crime committed as distinguished from the elements of the crime. The defendant was convicted of first degree assault. The case was presented to the jury under two alternative statutory theories. At the time, the statute allowed a conviction for first degree assault if a person
[1] with intent to cause serious physical injury to another person, ... causes physical injury to any person by means of a dangerous instrument; [or 2] ... [if] he intentionally performs an act that results in serious physical injury to another person under circumstances manifesting extreme indifference to the value of human life.
Alaska Stat. § 11.41.200(a)(1), (3) (emphasis added). Justice Rabinowitz in his dissenting opinion correctly noted that presenting both theories to the jury without a requirement of unanimity as to one or the other runs a serious risk of the jurors agreeing that a defendant acted with extreme indifference to the value of human life, but that only physical injury, as opposed to serious physical injury, was the result. Jurors could have thought that that was sufficient for a conviction of first degree assault when it was only a third degree assault. State v. James, 698 P.2d at 1168 (Rabinowitz, J., dissenting).
. Section 76-5-203 read as follows:
Murder in the second degree. — (1) Criminal homicide constitutes murder in the second degree if the actor:
(a) Intentionally or knowingly causes the death of another; or
(b) Intending to cause serious bodily injury to another, he commits an act clearly dangerous to human life that causes the death of another; or
(c) Acting under circumstances [objectively] evidencing a depraved indifference to human life, he [knowingly] engages in conduct which creates a grave risk of death to another and thereby causes the death of another [see State v. Fontana, 680 P.2d 1042 (Utah 1984) ]; or
(d)While in the commission, attempted commission, or immediate flight from the commission or attempted commission of aggravated robbery, robbery, rape, forcible sodomy, or aggravated sexual assault, aggravated arson, arson, aggravated burglary, burglary, aggravated kidnapping, or kidnapping, causes the death of another person other than a party.
(2) Murder in the second degree is a felony of the first degree.