There are plenty of people who don’t want evolution to be true or who don’t want to believe in global warming, and they’ll latch onto any shred of evidence to support their worldview. This is sometimes called confirmation bias: the inability to believe anything that challenges your preexisting conclusions. Scientists and science enthusiasts like myself are supposed to be immune to confirmation bias. We’re supposed to keep an open mind to new discoveries and new ideas. We’re supposed to be skeptics. Except I have a small confession: I have a little confirmation bias of my own.
I am firmly convinced there is life on Mars. I don’t think it’s anything more substantial than bacteria eking out an existence near the polar regions, but that’s still life, damn it. Maybe, if I’m lucky, something more complex is buried underground, protecting itself from deadly solar radiation and simultaneously from probing, human eyes.
At the moment, scientific evidence seems to support my belief. The Curiosity rover has found certain chemicals on Mars that suggest life could have evolved there. Curiosity also recently discovered evidence that there are small quantities of liquid water present in Martian soil, and since Martian sand storms often spread across the whole planet, scientists say it’s likely these traces of water are present everywhere.
There’s also the unresolved mystery of the methane gas in Mars’s atmosphere. Several different probes have detected it, but no one knows where it’s coming from. It’s possible bacterial life forms produce it. Unfortunately, the Curiosity rover is now telling us this methane doesn’t exist. The rover can’t find any sign of it. This challenges my faith in the existence of Martian bacteria, so when I read about these new test results I quickly commented that Curiosity must have made a mistake.
What will happen if Curiosity’s next experiment further challenges my beliefs? I’ll tell you what will happen: I’ll be heartbroken. I don’t think I’ll break down in tears, but I’ll probably feel a tiny bit depressed for a few days if not a few weeks. I’ll probably go into denial and argue that the new data only means the possibility of life currently existing on Mars is diminished, but it’s still not impossible. I might also start talking about how native Martian life might be so different from life on Earth that we wouldn’t recognize it even if we did find it.
I try to be a good skeptic. I try not to jump to conclusions, no matter how awesome those conclusions might be. So much as I may want there to be life on Mars, I have to try to curb my enthusiasm. I have to prepare myself for the possibility that I’m wrong. But it’s really difficult. I can understand what creationists and global warming deniers are going through. It’s hard to overcome confirmation bias, no matter what your confirmation bias is about.
P.S.: There is totally life on Mars, and I think some Martian creature probably threw a rock at the Curiosity rover. Click here to find out more.