Monthly Archives: January 2011

Weighing Evidence

John Doe is on trial for murder. The prosecutor demonstrated his culpability through forensic evidence. Seven witnesses that John has never met watched the crime, and their testimonies held up under cross-examination. John Doe even signed a confession.

But wait! The defense calls Jane Doe, John’s wife, to testify. She claims that John was with her at the time of the murder, and they were 100 miles away from the crime site. Her testimony also holds up under cross-examination. Despite the alibi that she provides, the jury convicts John Doe of murder.

After the trial, John’s mother claims that the jury ignored crucial evidence – the alibi – and that the judge was biased, the trial was rigged, and the American legal system is broken. Everyone else who saw the trial to its conclusion is convinced that John Doe is a murderer.


Nothing can ever be proven beyond a doubt. Any fact can have evidence presented against it. This is why trials, like the hypothetical one above, require a person’s guilt to be proven beyond reasonable doubt. John’s mother is taking an unreasonable stand, because the evidence for John’s guilt is strong and persuasive and the evidence for his innocence is comparatively weak. Jane Doe is biased, so her testimony is likely to be tainted. It is far more likely that she lied for the sake of her husband, and her lies were lucky enough not to be exposed. The witnesses were not biased and were presenting their testimony because it was true. John’s own testimony in the form of confession is especially compelling because he’s biased in his favor, and evidence that he presents against himself is very heavy. It is so heavy that the hypothetical situation above is never likely to occur, because a trial wouldn’t be needed once such evidence is gathered.

When we consider whether a proposition is true or false, we need to weigh all of the evidence. It should go without saying that to do this we need to have all of the evidence. Getting your information from a biased or slanted source is like hearing about the trial only through John’s mother… given just the information that she will provide, you’ll probably come to the same belief that she holds in John’s innocence.

It doesn’t shock me that Americans prefer to get their news from biased sources. Uncertainty is uncomfortable, weighing evidence is hard work, and no one wants to hear your opinion on a subject if you haven’t concluded anything yet. But it is shocking to hear opinions based on news from these biased sources stated as indisputable fact – there’s no such thing as fact beyond dispute, and this is even truer of opinions.

Let’s bring this topic away into the realm of a non-hypothetical debate – President Obama’s citizenship. The US Constitution states that a presidential candidate must be a natural-born citizen (Article 2, Section 1) to be eligible for the post, and also that a person born on US soil is immediately a citizen (14th Amendment). Obama was born in Hawaii. In response to allegations that this wasn’t true, he provided his birth certificate to the online community.

This doesn’t prove that he is an American citizen beyond all doubt – but nothing can be. It proves that he is a citizen beyond reasonable doubt. The “birthers” – those who wish to disprove Obama’s citizenship – are without exception Conservative Republicans that wish to see Obama fail. They are biased, and there’s a good reason for picking this topic to attack. It’s unlikely that Obama is cheating on his wife. It’s unlikely that he’s committing crimes. You’re not likely to see him say something stupid. He’s a smart guy with a cool temper, and he’s just not the easy target that our past presidents were. But this is just my opinion, and you can feel free to disagree with it.

Remember when Dan Rather reported a false story about President Bush? He apologized. We’re still waiting for that apology from the news reporting birthers.