Reasonable doubt
appropriately in criminal trials – but only if it features as part of a wider case against an accused person. There are grave dangers in an over-reliance upon it, particularly if it is the uncorroborated testimony of an expert witness or an alleged victim.
We know from experience that expert witnesses can make mistakes. We know that “evidence” can sometimes be dishonestly planted or manipulated.
Even when a particular sort of evidence could be used correctly, there is a danger that it will be misinterpreted. We know from experience that not only members of juries but also lawyers and judges sometimes misunderstand the nature and significance of statistical claims.
In the notorious prosecution of Sally Clark for the murder of her two babies, the case against her was based on the suggested improbability that two of her babies could have had natural cot deaths. Among the fallacies that were involved was the isolated focus on one particular unlikelihood. A comparison with other relevant, unlikely occurrences and events should have been undertaken.
For instance, although it is improbable that two babies of the same mother would die spontaneously of cot death, it could also be said to be highly improbable that a mother would murder her two babies.
Furthermore, it is fallacious to use statistical improbability as evidence that a particular event has not occurred. Highly improbable events do occur.
Someone will win the lottery no matter how unlikely it is to win. After the draw is made, we cannot use the improbability of winning as evidence that he or she did not win it.
Truth is not the same as truthfulness. Those witnesses who are truthful do not always say that which is true. One can be, for various reasons, honestly mistaken in one’s testimony.
If an alleged victim and an alleged rapist give inconsistent accounts of the event at issue, they might both be speaking truthfully. It might be the case that neither is lying – even if what one of them says is false.
Furthermore, accused people who tell lies when they give evidence are not necessarily guilty of that of which they are accused.
It seems inconceivable that it could be rationally concluded that, beyond all reasonable doubt, someone was guilty of a particular crime on the basis solely of the uncorroborated contested evidence of an alleged victim, even if the truthfulness of the testimony is not in question.
Juries must consider only relevant evidence. Furthermore, they must give the relevant evidence an appropriate weight. Otherwise, they cannot give someone a fair trial.
To give someone a fair trial for rape is not merely to come to the correct answer to the question: did he rape the alleged victim? It is to come to this answer for appropriate reasons when this is the correct answer.
It is the role of the courts to try those who are accused fairly and justly. It is not their function to secure convictions. If the laws and procedures are fair and just, we should accept the verdicts of the courts, whatever they turn out to be.
We should not tamper with the procedures in order to produce particular outcomes. l Hugh McLachlan is professor of applied philosophy in the Glasgow School for Business and Society at Glasgow Caledonian University