DNA testing still has shortfalls

Recently, the Wall Street Journal reported that a jury in my hometown convicted a man of murder. DNA evidence from the crime scene eventually supported his conviction. On the surface this case appears open and shut: the suspect lacks a solid alibi, has a motive for the killing and DNA evidence supports the prosecution’s claims. Boom, case closed, life in prison, no parole, right?
But as techniques for acquiring DNA samples improve and the overall presence of genetic science in courtrooms increases, trial law could potentially deteriorate into nothing more than a formal presentation of genetic evidence that, by itself, automatically determines guilt or innocence. As citizens who have direct contact with this system, we must educate ourselves about science and its limits in order to ensure that a technological tool does not replace law.
Genetic evidence is often viewed as irrefutable because numbers and statistics are attached. But blind faith in statistics, as most people know, can lead to equally blind results. And in the case mentioned above, the defense even spun damning evidence in their favor on the basis of irrefutability. They claimed that the results of the DNA test were irrelevant since everyone knows how accurate they are. The defendant would not have risked taking it had he any doubts about his innocence. Thus, he must be innocent. To be sure, this logic is a stretch, but the fact that defense lawyers around the country are using it should raise flags about our overreliance on this technique.
The first way to regulate DNA evidence is to consider all possible sources of error. As the defendant in this case correctly pointed out, contamination can occur, especially as the size of the sample needed to perform the tests decreases. Moreover, even if machines could perform all the tests behind glass walls, eliminating the possibility of contamination, the possibility of human corruption and human mistakes still remains. In the future, too, genetic alterations of an individual’s DNA might be possible, further graying this issue. Granted, some of these situations are extreme, but they should still raise doubts in our minds. Yet, if all fears of contamination and corruption are controlled, problems can still arise. Most importantly, with our society’s increasing dependence on and confidence in science and its applications, we must avoid applying the ultra-objective philosophy of science to human law. Unlike in science, where laws dictate exactly how initial conditions will influence final results, evidence in a trial should not inevitably lead to a standard conviction and formulaic punishment. Sword-swipe justice that ignores all outside circumstances and focuses on one type of evidence as superior is cold and insidious, especially considering eliminating all source of scientific and human error is not possible.
For exactly these reasons, education on the philosophy and methods of science, not just on formulas and facts that can be looked up in textbooks, must occur. Again, overdependence on and over confidence in scientific results are the main problems. We can no longer view magic boxes such as televisions and computers as science and assume that, because we have a knowledge of them, we have a reasonable knowledge of science. Although many people do realize it limits some of us to the point of fear about it, others do not understand that science has shortcomings. Abstract concepts such as justice and freedom in the determination of human behavior, for example, cannot be meaningfully understood in terms of hard science. (For one, consider that scientific ideas such as evolution deeply influence human beliefs and behavior; how can science hope to predict human behavior without also predicting all future scientific discoveries? And this does not even take into account the irrational nature of emotions.)
In these situations, not every scrap of DNA evidence points with certainty to one — and only one — possibility for the criminal. Equally important is that remnants of someone’s DNA does not necessarily mean he or she committed the crime.
Education about the powers and limits of science are needed to combat ignorance and provide citizens with intelligent tools for dealing with this problem. Doing so will both allay the fears of those who fear science might overrun their lives, leaving them sterile, and also curb those who believe whatever any smooth-talker with an ulterior motive might say just because the word science is attached. Remember that the polygraph, because of its supposed objectivity, was once similarly hailed as a great revolution and was soon shown to be woefully inadequate for trial settings. On the other hand, forensic science has certainly improved law in the last century.
Based on these trends, would O.J. Simpson have been acquitted if his trial occurred fifteen years in the future? Thank God we will never have to find out. But the question remains: Will trial law still be around in the 21st century? This issue will not settle itself quietly, either. In cases where evidence is scarce, sophisticated genetic screening might be used to determine that a defendant has the propensity toward destructive behavior, which could then be used as evidence against them. Education will be even more important then than it is now. Used properly, genetic science can be used in the same way forensic science has: as a tool that can aid the law — not as the law itself.
Without education, though, making compassionate decisions about the accused — a measure of our society’s nature — will be impossible.

Sam Kean is a senior English and physics major. He welcomes comments at [email protected]