delivered the opinion of the court:
Following a bench trial, the circuit court of Cook County convicted defendant, Elizabeth Ehlert, of the first degree murder of her newborn child (Ill. Rev. Stat. 1989, ch. 38, par. 9 — 1(a)), and sentenced her to 30 years in prison. The appellate court reversed, finding the evidence insufficient to prove the child was born alive. 335 Ill. App. 3d 467. We granted the State’s petition for leave to appeal. 177 Ill. 2d R. 315(a). For the reasons that follow, we affirm the judgment of the appellate court.
*195BACKGROUND
On August 21, 1990, defendant gave birth in her bedroom, in the home she shared with her two sons, her father, and her fiancé, Steven King. Two days later employees of the Salt Creek Park District discovered the baby’s corpse in a nearby lake. A creek that ran behind defendant’s house fed into the lake. Defendant’s conviction for murder was reversed on appeal because the prosecution presented irrelevant and highly prejudicial evidence at defendant’s jury trial. People v. Ehlert, 274 Ill. App. 3d 1026 (1995).
On retrial, the prosecution presented several witnesses who testified that between April and mid-August 1990, defendant repeatedly told them she was not pregnant. She told the witnesses that she had a cancerous tumor and she had seen several doctors about it.
King, who first met defendant in January 1990, testified that he moved in with her shortly thereafter. In April 1990, King noticed that defendant was gaining weight. Defendant told King that she had a growth or a cyst for which she had seen a doctor. In May 1990, defendant told King that she was bleeding and had received treatment from a doctor. They also discussed the need for a dilation and curettage. Defendant twice scheduled the procedure but was not able to have the surgery done. On July 18, defendant told King that she had ovarian cancer. Later in July, defendant told King that she had seen another doctor, and, in that doctor’s opinion, the tumors she had were not cancerous. Appointments to remove the tumors were cancelled because defendant told King she was bleeding. Subsequently, on August 17, defendant called King at work. She was hysterical. When King came home, defendant told King that tests at the doctor’s office showed she was actually six to eight weeks pregnant but the fetus was dead. She also told King that the doctor gave her a shot to induce an abortion within 48 hours.
Around 3 a.m. on August 21, 1990, defendant woke *196King up and told him she was in labor. King got out of bed. A few minutes later, defendant began screaming in pain. Rather than remain at her side and provide assistance, King left the bedroom because he did not want to see the miscarriage or the fetus. He did not turn the light on in the bedroom or the hallway. He did not press the alarm panic buttons on the security system in the hallway, which could have brought assistance from the police or paramedics. King further testified that he was hysterical, crying, frightened. He began pacing the hallway, living room and kitchen, and ventured into the basement. Twenty to thirty minutes elapsed. King then told defendant he was calling the paramedics. Defendant told King that her labor was almost over and asked him to get a plastic bag. He got a brown and green plastic bag from the cabinet under the kitchen sink. When he was 15 to 20 steps from the bedroom, he heard a single cry, lasting about two seconds. He took a few more steps down the hallway and asked defendant about the noise. Defendant replied he must have heard the family dog, which was in the bedroom. King did not question defendant further. Instead, without entering the bedroom, King reached in with the bag and, from the bed, defendant reached out and took the bag.
King testified that he next went to the living room area because he was not doing well emotionally. He did not hear any cries, sounds of choking or gasping for breath. He observed defendant, in her bathrobe, exit the bedroom and enter the bathroom. Defendant was not carrying the bag. She stayed in the bathroom for five minutes. During that time King did not hear any cries from the bedroom. Defendant returned to the bedroom. Again, without entering the bedroom, King repeatedly asked defendant if she was alright. Defendant told him to calm down. He heard some rustling as she picked up the bag but did not hear any crying or gasps for breath. *197He went back to the living room and from there observed defendant leave the bedroom with the plastic bag, which looked half full. He did not ask her what she planned to do with the bag but inquired again if she was alright. Defendant went to the kitchen area and King heard the back door slam. He went into the kitchen. Defendant was not there. He did not look to see where defendant went. Defendant returned two minutes later. When he asked her what she had done with the bag, she responded that she had thrown it into the creek. Defendant returned to the bedroom, and King could hear that she was in pain, screaming. He did not call the paramedics or press the alarm panic buttons. Defendant asked him to come into the bedroom and he entered the room for the first time. Defendant, in bed, was in the process of delivering or had just delivered the afterbirth. King cleaned up by pulling the towels and sheets from under her, placing them in another plastic bag and taking the bag to the kitchen for later disposal.
In the morning, King was upset and crying. Defendant contacted King’s mother, Mary Coward, who came over to the house. Coward asked King why he was upset. He related the whole episode to her and told her that he heard a baby cry. Later that day, King asked defendant about the cry he heard. She indicated that he had either heard the dog or imagined that he heard a cry.
On September 6, 1990, King was questioned at the police station. In a written statement, he told police that he was in the hallway with hands folded clenched, during the course of defendant’s labor. Defendant asked him to get a bag from the kitchen. As he returned with the bag, he thought he heard a baby cry. King then told the police that he would like to see an attorney and was informed that would not be necessary. At that point, King did not feel like a suspect. Later that same day, King received a telephone call from Commander McGregor, who told him *198that he did not think it was necessary for King to spend a lot of money on a lawyer. On cross-examination, King admitted that prior to the police interview, he was convinced he had either imagined the cry or heard the family dog. Also, at defendant’s first trial, King testified that at the conclusion of the police interview he believed he was a suspect in the case and hired an attorney.
Mary Coward testified that at approximately 9 a.m. on August 21, 1990, King called to say that defendant had the miscarriage and that he would call her later. That afternoon, defendant called to say that King was very upset and defendant asked Coward to come over. Once at the house, Coward sat next to King on the bed and comforted him. Coward nowhere testified that King told her he heard a baby cry.
Police officers who spoke with defendant on September 6, 1990, testified that she told them she had miscarried a fetus 15 weeks old and flushed it down her toilet. Police told her they had talked to King. Defendant first said she threw the miscarriage in the garbage, then she said King threw it in the garbage. When officers said King told them a different story, defendant said she did not remember what happened, but King’s account was probably true because “he doesn’t lie.” Police testified defendant admitted that she lied to King, and she had not seen any doctors throughout her pregnancy.
Further testimony showed that defendant told police her water broke two days before the birth, when she fell while trying to retrieve her son’s toy from a tree in her yard. She placed the fetus in a garbage bag and left the bag by a tree near the bank of the creek out back. When police asked if she threw the bag into the creek, she said, “No, unless you want me to say I did it, then I did it.” She then asked to have the baby buried next to defendant’s mother. In another interview, defendant told police that her ex-husband, not King, was the father of the *199baby. Defendant admitted that she had sexual relations with her ex-husband frequently in November 1989.
A few days later defendant called the police to say that she could not live with herself and wanted to tell them the truth. She asked police to assure her that King would take care of her children if she went to jail. Later she told police that when she went to the bathroom after delivering the dead fetus, King went to the bedroom, picked up the bloody towels and the baby and threw them out.
Dr. Mitra Kalelkar, assistant chief medical examiner for Cook County, testified at trial that when she completed the autopsy she could not determine to a reasonable degree of medical certainty that the baby had been born alive. She admitted that she found no unusual cause of death, so her “suspicion was that the baby drowned.” On direct examination, the prosecutor asked Dr. Kalelkar whether, at the completion of the autopsy, she “form[ed] an opinion within a reasonable degree of medical certainty as to whether or not the baby was born alive.” Dr. Kalelkar answered:
“At that time I had a suspicion that this baby was born alive and that the cause of death would be drowning; and pursuant to that suspicion, which I related to the police officers, I instructed them to investigate farther.”
Dr. Kalelkar later reiterated that after the autopsy she told police she “could not tell for sure whether it had been born alive.”
After police advised Dr. Kalelkar of their investigation, she concluded in December 1990 that the baby had been born alive and it had drowned. Dr. Kalelkar relied on evidence that defendant had lied to several persons about her pregnancy and her visits with doctors, and, most particularly, she relied on Kang’s statement to police that he thought he heard a baby cry.
Dr. Kalelkar further testified she saw no evidence in the decomposing corpse of any natural disease process. *200She found air in the lungs, hemorrhage on the skull due to natural causes, and some blood on the umbilical cord. Dr. Kalelkar admitted that the air she found in the lungs could have resulted from decomposition rather than breathing. She also stated that “there is no specific way of telling whether that rip [of the umbilical cord] was ante mortem or postmortem.” Blood may remain in the umbilical cord after the baby dies. Lastly, while the hemorrhaging suggested that the baby was alive when the head went through the vaginal canal, it did not show that the baby survived the birthing process.
On cross-examination, Dr. Kalelkar admitted that a baby could die due to partial placental abruption. Furthermore, a baby could go into shock if it lost 60 milliliters of blood in the birthing process.
Two pathologists testified on defendant’s behalf. Both pathologists agreed with Dr. Kalelkar that the autopsy findings could not support a finding to a reasonable degree of medical certainty that the baby was born alive. Dr. John Pless stated that the hemorrhage on the skull could occur even if the fetus had already died. Dr. Pless noted that if placental abruption killed the fetus shortly before delivery, one would expect findings like those present here. He further stated that a fall from a tree could cause the placenta to detach from the uterine wall and result in fetal death. The force of the fall need not be great if the trauma occurred at a place that maximized impact on the placenta. Dr. Pless testified that the baby could also have died from blood loss in the birthing process or obstruction of the airway. Water and bacteria probably would have eliminated any mucus plugs that might have caused asphyxiation.
Dr. Pless also agreed with Dr. Kalelkar that no marks on the body showed disease or physical injury. He noted that decomposition probably would have eliminated any evidence the baby died from infection. He also agreed *201with other doctors that a newborn faces a greater risk of death from asphyxiation or blood loss in an unattended home birth than in a hospital deliveiy.
Dr. Robert Kirschner found there was sufficient evidence to conclude that the baby was alive when labor began. However, he found the evidence insufficient to show that the baby survived labor. Dr. Kirschner testified that even if the baby was alive at birth, it may have died from failure to clear its airways, blood loss or infection. He noted that, if a child had marked respiratory distress at the time of birth, it might give a feeble cry, then die. He agreed with the prosecutor that a cry would show live birth.
At the conclusion of the trial, the court expressly found credible King’s testimony that he heard a baby cry. The court recognized that King might have adequate motive to lie and to tell the police that he heard a baby cry. However, had King wanted to minimize his involvement it would have been better for him to deny that the baby was born alive. The court found King’s testimony, together with the medical testimony, sufficient to show that the baby was born alive. The court concluded that defendant was guilty of murder.
As noted by the appellate court, the circuit court did not comment on the medical testimony that the baby may have died after a live birth from various noncriminal causes. Also, the circuit court did not make any findings as to the cause of the baby’s death or the criminal acts defendant committed resulting in the baby’s death. The court sentenced defendant to 30 years in prison.
On appeal, defendant argued that the evidence was insufficient to show that the baby was born alive. Further, defendant maintained that, if the baby was born alive, the evidence was insufficient to show that defendant performed any act after birth to cause the death of the baby or that defendant had the mental state required *202in a prosecution for murder. The appellate court agreed that the evidence was insufficient to prove live birth and reversed defendant’s conviction. 335 Ill. App. 3d at 474. Because of its resolution of the issue of live birth, the court did not address the additional arguments for reversal.
We granted the State’s petition for leave to appeal.
ANALYSIS
In this court, defendant contends the evidence was insufficient to prove her guilty beyond a reasonable doubt. Defendant reprises her arguments that the State failed to show that the baby was born alive and, if the baby was born alive, that defendant committed a criminal act resulting in the death and defendant had the requisite mental state for murder.
A criminal conviction will not be set aside on appeal unless the evidence is so improbable or unsatisfactory that there remains a reasonable doubt of the defendant’s guilt. People v. Tenney, 205 Ill. 2d 411, 427 (2002). The question on review is whether, after viewing the evidence in the light most favorable to the prosecution, any rational fact finder could have found defendant guilty beyond a reasonable doubt. People v. Brown, 185 Ill. 2d 229, 247 (1998); People v. Eyler, 133 Ill. 2d 173, 191 (1989). This standard of review applies in all criminal cases whether the evidence is direct or circumstantial. Tenney, 205 Ill. 2d at 427; People v. Gilliam, 172 Ill. 2d 484, 515 (1996).
As noted above, the circuit court convicted defendant of the murder of her newborn. Proof of an offense requires proof of two concepts: first, that a crime occurred, or the corpus delicti, and second, that it was committed by the person charged. People v. Cloutier, 156 Ill. 2d 483, 503 (1993). In a prosecution for murder, the corpus delicti consists of the fact of death and the fact that death was produced by a criminal agency. People v. *203 Garrett, 62 Ill. 2d 151, 172 (1975). In addition, where the State alleges that the defendant has killed her newborn, the State must prove that the infant was born alive. People v. Greer, 79 Ill. 2d 103, 110 (1980); People v. Ryan, 9 Ill. 2d 467, 471 (1956). It is axiomatic that a defendant cannot be convicted of the murder of a person who has already died. W. LaFave, Substantive Criminal Law § 14.1, at 419 (2d ed. 2003).
The appellate court believed that the State failed to prove defendant’s baby was born alive. In particular, the appellate court found insufficient the State’s evidence that the baby showed signs of independent life once expelled from defendant’s womb. The appellate court noted agreement between the prosecution’s medical expert and defense experts that the physical findings alone did not prove live birth to a reasonable degree of medical certainty. 335 Ill. App. 3d at 471. The appellate court further noted that in reaching her conclusion that the baby was born alive, Dr. Kalelkar relied on King’s statement to police that he thought he heard a cry. 335 Ill. App. 3d at 471. And, although Dr. Kalelkar recited evidence that defendant did not want the child and lied to neighbors about the pregnancy, she did not explain why an unwanted child would have a better chance of surviving the birth process or how that evidence in any way showed live birth. 335 Ill. App. 3d at 471. Lastly, the appellate court considered, and found wanting as proof of live birth, King’s testimony that he heard a baby cry. 335 Ill. App. 3d at 471. The court found it significant that King did not see the baby when he heard the cry. 335 Ill. App. 3d at 471. The baby could have cried during the birthing process, and King could not testify otherwise. 335 Ill. App. 3d at 471.
Because the appellate court found insufficient the State’s evidence that the baby was born alive, the court did not consider defendant’s alternate arguments that *204the evidence was insufficient to prove either criminal agency or the requisite mental state for murder. 335 Ill. App. 3d at 468.
In this court, the State argues the appellate court failed to apply the proper standard of review, that is, the appellate court failed to consider the facts in the light most favorable to the State, because the appellate court did not accept the fact that the baby cried. We disagree with the State’s reading of the appellate court opinion. We believe the appellate court applied the appropriate standard of review.
The State also urges that we discard the common law requirement that a baby must be totally expelled from the mother’s womb and establish independent life before it is considered alive. The State asserts that the common law requirement, necessary because of the lack of medical knowledge and high infant mortality rates prevalent in the 18th century, is now antiquated. According to the State, medical advances have eliminated the need for a presumption of death during childbirth. The State asks us to adopt the view of the court in People v. Chavez, 77 Cal. App. 2d 621, 176 P.2d 92 (1947), that a viable fetus “in the process of being born” is a human being within the meaning of the homicide statutes.
In Greer this court held that to be born alive a fetus must be totally expelled from the mother and show a clear sign of independent vitality. 79 Ill. 2d at 103. In urging that we adopt the reasoning of Chavez, the State is thus asking that we reconsider our ruling in Greer. In keeping with the doctrine of stare decisis, prior decisions should not be overruled absent good cause or compelling reasons. People v. Robinson, 187 Ill. 2d 461, 463-64 (1999); Moehle v. Chrysler Motors Corp., 93 Ill. 2d 299, 304 (1982). Further, we note that the State has raised arguments in this case that were considered by the court in Greer. We need not opine on the merits of the State’s *205arguments, however, because we note an alternate basis for reversal of defendant’s conviction. Defendant argues, and we agree, that even assuming the baby was born alive, the evidence was insufficient to show that death resulted from defendant’s criminal agency.
The State’s theory of the case was that defendant, having hidden her pregnancy, gave birth to a live baby, placed the baby into a plastic bag, and either threw the bag into the creek or placed the bag next to the creek where an animal presumably dragged it into the creek. To prove this theory, the State presented evidence from King, defendant’s paramour. King’s testimony was that, when he was 15 to 20 steps from the bedroom, he heard a single cry, lasting about two seconds. King proceeded down the hallway to the bedroom. Without entering the bedroom, King reached in with the bag and, from the bed, defendant reached out and took the bag. King testified further that, after he handed the plastic bag to defendant, he did not hear any cries, sounds of choking or gasping for breath. Defendant left the baby unattended in the bedroom for five minutes. During that time, King did not hear any cries from the bedroom. King saw no signs of motion in the bag when defendant took the bag from the house.
The State also relied on the testimony of the medical examiner, Dr. Kalelkar. At the time of the autopsy, Dr. Kalelkar found no unusual cause of death. No marks on the baby revealed foul play. Dr. Kalelkar testified on direct examination that, after performing an autopsy, she surmised that the baby drowned. Dr. Kalelkar distinguished between cause of death and manner of death: “The manner basically is the circumstances surrounding death” and could be natural, homicide, suicide, accident, or undetermined. After Dr. Kalelkar performed the autopsy, she suspected that the baby was born alive because the body had hemorrhaging on the head, aerated *206lungs, antemortem bleeding around the umbilical cord, and no natural diseases. Dr. Kalelkar then stated both that she did and that she did not determine the cause of death at the time of the autopsy to a reasonable degree of medical certainty. On direct examination, Dr. Kalelkar initially asserted, “At the time when I did the autopsy, *** I did not form an opinion. I verbalized to the police officers what my suspicions were or what I thought had happened to this child, and I instructed them to go and get or to investigate the matter further.” When asked by the prosecutor when she formed her opinion regarding the cause of death, Dr. Kalelkar responded, “As to the cause of death was [sic] pretty obvious at the time that I did the autopsy because of the fact that the baby was recovered from water.” The prosecutor clarified that he was addressing the cause of death, not the manner of death. Dr. Kalelkar then stated:
“In my opinion, and I so verbalized it to the police officers who were present at the time of the autopsy, that based on the fact that this body was recovered from water and based on the fact there was no evidence of any other cause of death, injuries or natural disease processes, the cause of death would be drowning.”
Thus, Dr. Kalelkar apparently determined the cause of death at the time of the autopsy, but did not determine the manner of death until she consulted with the police. Still, on the death certificate, she handwrote “pending police investigation” in the space for cause of death and left blank the space for manner of death.
After Dr. Kalelkar advised the police of her suspicions, the police later advised her of the results from their investigation, which confirmed her suspicions, including her initial impression that the infant was born alive. In fact, Dr. Kalelkar observed that a “very significant” part of the police report was the fact that King “heard a sound which was akin to a baby crying.” Dr. Kalelkar continued: “[H]earing the baby cry is an indication that a baby is *207born alive, and my physical findings showed that there was air in the lungs. Now granted that air in the lungs could have come from decomposition changes, but given this fact as well as the physical findings and all the other facts surrounding this case, everything tied together.” Dr. Kalelkar listed the manner of death “based on all the circumstances” as homicide.
On cross-examination, however, Dr. Kalelkar’s account of her opinions changed. She testified that at the time of the autopsy, she could establish neither a cause nor a manner of death:
“Q. And at the end of the time that you completed that autopsy you told those police officers that you could not determine for sure whether or not this baby was born alive, right?
A. At the time I only had a suspicion. That is correct.
Q. And you told them that you suspected that the cause of death would be drowning if you could prove that the baby was born alive, right?
A. I don’t recall what I told them exactly, but I do remember that I suspected that the baby was born alive because it was a full-term baby and I did not find any natural cause of death, and that the cause of death was drowning because the baby was found in water.
Q. Okay. But you told them that you could not tell for sure whether it had been born alive at that point, right?
A. I agree.
Q. Okay. And you told them that you couldn’t establish or prove at that point what the cause of death was, right?
A. That is correct also.
Q. You didn’t tell them I know the cause of death but I can’t give you a manner of death at that point, did you?
A. No, I did not.
Q. And at that point you filled out or shortly after that you filled out a death certificate in which you put, under cause of death, pending police investigation, right?
A. That is correct.
* * *
Q. And down a little bit lower on the left part of the *208certificate there is a space where you can put the manner of death such as natural or homicide or whatever, right?
A. That is correct.
Q. Now you didn’t put anything in there?
A. No. That was left blank.
* * *
Q. All right. And you later then changed the death certificate in the sense that you filled in homicide [as the manner of death] and you put in drowning as the cause of death, right?
A. Correct.
Q. So essentially between the time that you filled out that first death certificate and the time you fiUed out the second death certificate, what you got was information from the police, right?
A. Yes.
Q. It wasn’t a matter of you having gotten further information from your autopsy that caused you to change the death certificate, was it?
A. There was no change in the death certificate. There was not, you know — There was no change in the cause of death, yet the police investigation just confirmed what I had originally suspected as to the cause of death.”
Dr. Kalelkar agreed that the final death certificate was a “sort of continuation” of what she had done before receiving the police reports. According to Dr. Kalelkar, this was a generally accepted practice in her field.
One of the defendant’s forensic experts, Dr. Pless, disagreed that it is a generally accepted practice among forensic pathologists to base cause of death opinions on information in police reports:
“We are engaged in a scientific discipline in which the opinions regarding cause of death need to be related to findings in the examination, specifically in the case of forensic pathology in the autopsy. And if those findings aren’t there, then it’s inappropriate to develop an opinion based on what someone heard or said. That’s completely outside the discipline of science.”
But Dr. Kalelkar’s drowning surmise is problematic for another reason. King testified that, after hearing *209what he thought was a short cry from outside the bedroom door and down the hall while defendant gave birth, he did not hear the baby or see her move inside the plastic bag during the 5 to 10 minutes before defendant disposed of the bag. Further, Dr. Kalelkar did not find debris in the baby’s lungs or in the air passages. She also did not find evidence of pulmonary edema, indicative of water in the lungs. Such findings, although not present in all cases, can lend support to a conclusion that death is by drowning. Justices Thomas and Garman note that King “would not hear cries or see the baby move if defendant had already suffocated it.” 211 Ill. 2d at 231 (Thomas, J., dissenting, joined by Garman, J.). In response to a question by the trial judge, Dr. Kalelkar discounted this theory: “It could be suffocation, but the fact is that the baby was found in water. So automatically because the baby is found in water, you know, I determined it was drowning.”
In addition to the fact that there is no evidence of record to suggest that defendant suffocated the infant, on cross-examination Dr. Kalelkar agreed that the infant could have died from natural causes: anoxia from a displaced placenta, asphyxiation by mucus or other fluids, or loss of blood and shock. Evidence that defendant placed her already-dead infant’s corpse in a plastic bag, then placed that bag near or into a creek feeding into a golf course retention pond, shows that defendant is capable of doing terrible and desperate things. We require more of the State than this in a murder prosecution.1
Looking at the evidence in the light most favorable to *210the prosecution, we are left with a reasonable doubt as to defendant’s criminal agency. As this court emphasized in People v. Martin, 26 Ill. 2d 547, 551 (1963), the relationship between the defendant’s “criminal agency and the cause of death [may not be] left *** to inference and speculation.” This court may reverse a conviction where the evidence is so unreasonable, improbable, or unsatisfactory as to justify a reasonable doubt of the defendant’s guilt. People v. Ortiz, 196 Ill. 2d 236, 259 (2001).
We note that in analogous circumstances, the courts of sister jurisdictions reversed convictions for insufficient evidence of the mother’s criminal agency. State v. Doyle, 205 Neb. 234, 238, 287 N.W.2d 59, 62 (1980) (“At best the evidence, almost exclusively circumstantial in nature, disclosed that a child was born to the defendant and that the child died. The pathologist was unable to testify as to any cause of death and could not testify that the cause of death was not from natural causes”); Lane v. Commonwealth, 219 Va. 509, 515, 248 S.E.2d 781, 784 (1978) (“We hold that the evidence was insufficient to show beyond a reasonable doubt that the child’s death was caused by a criminal act of the defendant and that the corpus delicti had not been proved”); Graham v. State, 6 Ark. App. 376, 642 S.W.2d 342 (1982). See also Taylor v. State, 108 Miss. 18, 25, 66 So. 321 (1914) (“The examination of the body of the child by these physicians failed to disclose any evidence of violence to its person, and their opinion that it died from suffocation seems to be based upon the fact that their examination also failed to disclose any reason why the child should have died from a natural cause”).
*211Justices Thomas and Garman clearly disagree with our conclusion in this matter, and we feel compelled to address several aspects of their separate opinion as well as comment on the disparaging tone and tenor they use in the opinion. As an initial matter, we take issue with their characterization of our holding. Today’s opinion does not, in any way, make it legal in Illinois for a mother to murder her newborn infant. See 211 Ill. 2d at 216 (Thomas, J., dissenting, joined by Garman, J.). Infanticide remains a crime in Illinois. What today’s opinion does do, however, is reaffirm this court’s commitment to the time-honored notion that, in Illinois, a conviction for murder will not be allowed to stand in the absence of proof beyond a reasonable doubt that the convicted defendant caused the victim’s death.2 The implication that the *212justices in the majority clearly sanction infanticide is unfounded and has no place in proper judicial discourse. Justices Thomas and Garman assert:
“The majority seems to base its entire reversal on a curious critique of the medical examiner’s testimony. The bitter irony here is that what troubles the majority about Dr. Kalelkar’s conclusion is the precise problem with the majority’s own analysis. The majority is actually troubled by the fact that Dr. Kalelkar considered the known facts of the case in reaching her conclusion that the baby drowned. Of course, the absence of such an analysis is the glaring flaw in the majority’s own opinion. The majority focuses solely on the medical testimony involving the baby and fails to consider all of the other circumstantial evidence pointing directly to defendant’s guilt.” 211 Ill. 2d at 229 (Thomas, J., dissenting, joined by Garman, J.).
The conclusion that we reach is neither curious nor “bitter [ly] iron[ic].” We do not say that nothing matters except for the medical testimony. The State said that, by implication, when it offered nothing else to prove defendant killed her infant. Certainly, the record is replete with evidence of what Justices Thomas and Gar-man characterize as defendant’s “deceit.” The flaw in their dissent is their willingness to equate this deceit with evidence of criminal agency.
Defendant need not disprove her guilt. An accused’s right to demand proof of the State’s case beyond a reasonable doubt is a protection of “surpassing importance.” Apprendi v. New Jersey, 530 U.S. 466, 476, 147 L. Ed. 2d 435, 447, 120 S. Ct. 2348, 2355 (2000). This right has formed the bedrock of constitutional criminal procedure for centuries: “Although virtually unanimous adherence to the reasonable-doubt standard in common-law jurisdictions may not conclusively establish it as a *213requirement of due process, such adherence does ‘reflect a profound judgment about the way in which law should be enforced and justice administered.’ ” In re Winship, 397 U.S. 358, 361-62, 25 L. Ed. 2d 368, 374, 90 S. Ct. 1068, 1071 (1970), quoting Duncan v. Louisiana, 391 U.S. 145, 155, 20 L. Ed. 2d 491, 499, 88 S. Ct. 1444, 1451 (1968). Thus, our opinion is not a blueprint for murder, but rather a blueprint echoing a concept that has well served the Anglo-American criminal justice system since the Magna Charta was signed in 1215 — namely, due process of law. We are unwilling to redraft that august guarantee.
Simply stated, the fact that defendant is “probably” guilty does not equate with guilt beyond a reasonable doubt. We must point out that in criminal prosecutions, the standard of proof is not by a preponderance of the evidence, but rather proof beyond a reasonable doubt.3 *214We acknowledge that on any particular issue conscientious jurists can respectfully disagree, and it is the prerogative of Justices Thomas and Garman to take issue with the majority’s analysis. However, these justices should do so in a civil and judicious manner. The dissent Justices Thomas and Garman filed today borders on demagoguery when the dissenting justices choose to cross the bounds of collegiality by insisting that the members of the majority have ‘‘irresponsibly]’’ ignored evidence (211 Ill. 2d at 217, 249 (Thomas, J., dissenting, joined by Garman, J.) and 6‘disingenous[ly]’’ warped the standard of review in order to free a convicted murderer. Suffice it to say, it is difficult for this court to expect practitioners to engage in civility in the practice of law when members of this court are unwilling or unable to engage in respectful legal discourse in a published opinion.
Finally, the prediction by Justices Thomas and Gar-man that murderers will use this opinion as a guide to commit their crimes is unrealistic. First, it assumes that criminal minded mothers intent on killing their newborn infants will consult this court’s opinions before they act. Second, and more importantly, it assumes that the State will often have to proceed to trial against a defendant charged with murdering her newborn infant armed with only equivocal testimony from the medical examiner regarding the cause and manner of death based on testimony from the defendant’s boyfriend, who may have *215heard a short cry, but saw nothing. The holding in this case is as unique as its facts and is limited to them.
CONCLUSION
Our observations in People v. Smith, 185 Ill. 2d 532 (1999), regarding the burden of proof the prosecution must meet to obtain a criminal conviction are most appropriate in this case:
“What is involved here is the standard of proof which is applicable to all crimes. That is to say, conviction beyond a reasonable doubt. Whether the crime charged be trespass, shoplifting, armed robbery, or murder, the test is the same. The burden of meeting this standard falls solely on the prosecution. If it fails to meet this burden, a defendant is entitled to a finding of not guilty. No defendant is required to prove his innocence.
While a not guilty finding is sometimes equated with a finding of innocence, that conclusion is erroneous. Courts do not find people guilty or innocent. They find them guilty or not guilty. A not guilty verdict expresses no view as to a defendant’s innocence. Rather, it indicates simply that the prosecution has failed to meet its burden of proof. While there are those who may criticize courts for turning criminals loose, courts have a duty to ensure that all citizens receive those rights which are applicable equally to every citizen who may find himself charged with a crime, whatever the crime and whatever the circumstances. When the State cannot meet its burden of proof, the defendant must go free. This case happens to be a murder case carrying a sentence of death against a defendant where the State has failed to meet its burden. It is no help to speculate that the defendant may have killed the victim. No citizen would be safe from prosecution under such a standard.” Smith, 185 Ill. 2d at 545-46.
As in Smith, we do not imply that defendant is innocent of the crime charged. The State’s evidence of criminal agency resulting in death was simply insufficient. This court cannot affirm a conviction based on speculation and conjecture. Accordingly, we affirm the judgment of *216the appellate court reversing defendant’s conviction of murder.
Appellate court judgment affirmed.