Consensus and Confidence: 2 Important Questions to Ask About Every Scientific Idea

These are the first two questions I use to quickly sort scientific claims into “worth considering” or “rubbish,” and I think others might find them useful too. Every day I see scientific claims of all sorts floating around the internet, and that’s pretty great to see because I’m pretty excited about science. Unfortunately I don’t have the time to verify every claim by investigating thoroughly. Frankly, nobody does. So a lot of these claims just get ignored as irrelevant to life (the multiverse theory is super great!), but others are a bit more important for how I live my life and what organizations I support (Does sexual reorientation therapy work? (no, it doesn’t)), but I may still not have time to thoroughly research.

Fortunately, without needing to get a PhD, I use two simple questions that I think can show what’s really going on with a scientific claim pretty quickly and reliably.

Question 1: Is there good consensus about the claim?

That is, do the experts in the field mostly agree with the claim? Science is a critical community effort. If there is a good argument against an idea, scientists will gleefully point it out. I know I certainly do, and I haven’t met a scientists yet who doesn’t enjoy disagreeing with other scientists where possible. So when there is strong agreement among experts, who should know of any good arguments for or against, then that’s strong evidence that the idea is good.

A handy thing about scientists is that they organize themselves into professional organizations to share what they agree or disagree on, so it’s often not hard to figure out if there is good consensus. You can look at any large psychology association like the APA and they will tell you that trying to make a gay person straight isn’t a good idea. Because the APA is clear about the subject, and because the APA represents the experts in the field, I can confidently say that there is good consensus here.

This is the first question I ask because it immediately weeds out most whackos. I can probably find someone with a PhD to agree with any nonsense idea I can think of, and that’s awful for confirmation bias. If I really wanted to believe the sun revolves around the Earth, I can find a person with a PhD to agree with me (even with arguments from the Bible!). But as soon as I ask about consensus, it becomes pretty clear if a scientific idea is even worth considering or not. Even though I am not an astrophysicist, I’m pretty confident that geocentrism is not a serious scientific idea these days. The American Astronomical Society doesn’t even mention it, so there’s no consensus saying geocentrism is accurate.

Question 2: What is the strength of confidence in the claim?

The first questions clears away most garbage, but even a good idea might not be super useful or clear. Confidence is a term scientists use to mean how certain they are that new evidence will not overturn an idea. Confidence can often be calculated by using statistical formulas too boring for me to elaborate on here. Low confidence often also means low consensus. However, low confidence despite consensus could happen when there just isn’t much evidence for or against an idea yet, but there also aren’t any other good options.

For example: Any serious biology association concerned with the origins of life will have articles about the chemical evolution of life, because there is good consensus that it probably happened somehow. It makes sense scientifically, we have some evidence, so it’s a good idea with good consensus. But how confident are we about how that happened? Not at all, really. In fact, there is no standard theory of the origin of life, because scientists just aren’t sure and are honest about that. New evidence could very easily completely change our understanding on this topic.

On the other hand, an idea we have high confidence about almost certainly will never be overturned by further evidence. Things like the Earth orbiting the Sun, our planet being more than 4 Billion years old, we juts have so much clear evidence about. There is always a chance of new evidence overturning an idea in science, but sometimes it’s completely unreasonable expect it to happen.

So if someone were to tell me about a really neat mechanism for the origin of life that involved chemical evolution, the claim would make it past my first question. There is good consensus that it’s a good idea. But as soon as I ask about confidence level, it would become clear that it’s a weakly evidenced idea. Still interesting, slightly less exciting, and a lot less useful.

I think the above two questions can let anyone quickly and reliably sort science claims into being garbage, worth considering, or probably true. Do you have different questions you use for this? Or disagree with mine? As a scientist, I’d be interested to hear about it!

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