Court Opinion

ID: 9777696
Source: CourtListenerOpinion
Date Created: 2023-08-29 20:20:01.329772+00
Date Added: 2024-06-11T07:32:59.552287
License: Public Domain

QUINN, Justice,
concurring.
I concur in the resolution of point one but for reasons different than the majority. The evidence obtained from the use of Bayes’ Theorem may be acceptably scientific and satisfy one prong of the Kelly test described *253by the majority. However, for the reason described below, I believe it to be too misleading and confusing to satisfy the second prong. Therefore, it was inadmissible. Nevertheless, the error was harmless given the rather undisputed and conclusive DNA evidence establishing that appellant fathered the child.
One is presumed innocent of a crime until proven guilty beyond a reasonable doubt. Tex.Pen.Code Ann. § 2.01 (Vernon 1994); Tex.Code Crim. Proc. Ann. art. 38.08 (Vernon Supp.1998); Homan v. State, 662 S.W.2d 372, 374 (Tex.Crim.App.1984) (en bane); Delo v. Lashley, 507 U.S. 272, 278, 113 S.Ct. 1222, 122 L.Ed.2d 620, 628 (1993). Admittedly, the standard actually speaks of the State’s burden of proof. But, it implicitly connotes that the fact finder must begin the journey of determining guilt with the belief that the accused did not do the criminal act until the State proves he did.
For instance, one can picture a child stacking ten blocks on top of each other. Before he can reach the pinnacle with the tenth block, the other nine must first be placed in order. So, the child starts with the first, then second, then third, fourth, fifth, sixth, seventh, eighth, and ninth. Eventually, the tenth is set atop the stack and his task is complete. The burden of proof imposed upon the State is analogous to stacking blocks, for the prosecutor is obligated to set bits of evidence, like blocks, atop each other to reach the level of proof mandated by law. And, before it can place the last block on the stack to achieve proof beyond a reasonable doubt, the other nine must first rest under it. He cannot simply ask the fact finder to presume that one or more of the nine are there. Rather, they must actually be there. And, therein lies the problem with using Bayes’ Theorem. For the theorem to have any meaning, the State is implietly asking the fact finder to presume that one or more of the blocks exist. That this is so can be seen from the application of the theorem to the circumstances at bar.
Here, the State was trying to prove that the appellant sexually assaulted the victim by having intercourse with her. One way to prove that he had intercourse was to prove that he was the infant’s father. Indeed, if he was the father then it would be quite reasonable to deduce that he had intercourse with the mother.1 Here, proving fatherhood was done by sampling the blood of the appellant, the victim, and the child. Once the blood was taken from each, it was then compared to determine the existence of common genetic markers. After that, the State endeavored to determine the number of men needed in a randomly selected pool for one of those men to have the same markers found in the comparison. That number constituted the paternity index, which here was 14,961. The index alone, however, did not illustrate that the accused was the father, but rather that a certain number of randomly selected men were needed in the pool to find one with the same genetic markers. What allegedly illustrated fatherhood was the application of Bayes’ Theorem to the index, for that resulted in the probability (or percentage chance) of paternity.
So, to find the relevant probability under the theorem, the paternity index was multiplied by an assumed percentage chance that appellant was the father. The assumed chance used here was 50% because that was purportedly neutral, ie., a 50% chance that he was the father and a 50% chance that he was not.2 This resulted in a product of 14,-961 (14,961 x 50/50 = 14,961). One (1) was then added to the product for a sum of 14,962. That sum was then divided into 14,-961 to derive the percentage chance that the accused is the father, and the percentage chance derived here equaled 99.99%.3 According to the supposed evidence obtained *254through the use of Bayes’ Theorem, there was a 99.99% chance that appellant fathered the infant, which for all practical purposes also meant that there was a 99.99% chance that appellant had intercourse with the mother.
As can be seen, for the State to convert its DNA testing into a statistic, it used a formula (Bayes’ Theorem) containing an element mandating the presumption that appellant had intercourse with the victim. And, most ironically, the particular act which was presumed to have occurred just happened to be the same criminal act not only which he was accused of committing, but also which the State was obligated to prove through actual evidence. So, in plugging Bayes’ Theorem into my building block example, what the equation does is ask the fact finder to assume that one or more blocks necessary to prove guilt already exists when the State has yet to prove their existence. And, in my view, that is inimical to the presumption of innocence (or burden of proof imposed on the State) and renders the theorem and its statistical result highly misleading.
As to Dr. Eisenberg’s statement that the use of a .5 factor is neutral, I find the comment misleading when applied in the setting of a criminal trial. In the realm of statistics, a 50/50 chance is neutral; that is, it accurately depicts the notion that something is as likely as not to occur. Yet, to' be innocent, according to Black’s Law Dictionary, means to be free of guilt or guiltless. That means, in the common parlance of a layman, that the accused did not do the act. So, to presume one innocent is to presume that he did not do the act; it is not to presume that there is a chance he did the act. If the presumption were to be assigned a location on the .00 to 1.00 statistical scale used by Eisenberg, it would have to lie at .00. This is so because only there can it be said with certainty that he did not do the act. Placing it elsewhere on the scale would suggest, however slight, that he did. Because locating the starting point at .00 would render Bayes’ Theorem ineffective illustrates to me why it had no place in the trial to begin with.
I cannot deny the value of math in our day, time, and profession. Yet, while statistics and mathematical principles may facilitate resolution of legal questions, they cannot supplant criminal jurisprudence. Two plus two will always equal four, for that is an arithmetic principle. But, before two plus two can equal guilt, an immutable principle of criminal justice mandates that the State prove two and two exist in the first place. That is part and parcel of the presumption of innocence. And, all attempt to circumvent that principle must be avoided.
Nevertheless, I must also acknowledge the value of science and heed its teachings. The science here pivotal was that of DNA extraction and comparison. The evidence of extraction and comparison proffered by Dr. Eisenberg (sans conversion into statistic) established that the child could have obtained her DNA only from her mother and appellant or appellant’s identical twin. Moreover, while appellant did little to contest that DNA evidence, he utterly negated any possibility that his identical twin could have been the father by admitting he had no twin. Given these circumstances and this evidence, I must conclude that any error in admitting the results garnered via Bayes’ Theorem was harmless.

. This is not to say that fatherhood indisputably proves intercourse, however. As a result of modern science, a female may become pregnant without ever having intercourse with anyone.

. According to the testimony, the assumed chance can be most any that one wants to input, such as 50% as here, or 25%, 10%, or 1%, but it has to be more than 0%. If it were zero then the product derived from multiplying the percentage chance by the paternity index would be zero. In other words, the use of zero would result in a finding of no chance of paternity.

.14,961 / (14,961 + 1) = 99.99.