Strong Opinions Strongly Overrated

Today Avdi tweeted about this lovely article debunking “strong ideas, loosely held”.
The gist is, yo! stop talking like you’re sure about stuff. It makes it hard for other people to chime in, and it anchors you, making it hard to let go of your opinion.
The simple trick is to quantify your certainty, below 100%. “I’m 90% sure…” or “At 80% confidence…” This helps you because it’s easier to reduce confidence from 90 to 60, given new information, than to change an absolute (P=1) belief.

Like consequences, beliefs are not yes/no, black/white, all/nothing. We hold beliefs at different confidence levels. There’s a book about this: Probabilistic Knowledge, by Sarah Moss. With academic rigor, she proposes that we don’t believe with 50% confidence that Go is the best language for this. Instead, we believe that “There is a 50% chance that Go is the best language for this.” Modeling belief this way leads to some cool stuff that I haven’t read yet; we can do math on this. And it’s how our brains really work; we are constantly choosing action while uncertain.

This also shows up in How to Measure Anything, which uses experts and confidence intervals to get rough measurements of risk and expected outcomes. This can help with decision making. Dan North talks about this with software estimation: the trick is not to ask for a single number “how long will it take” but instead, “It’ll definitely take at least X” and “I’d be embarrassed if it took more than Y”. This gives you a 90% confidence interval, and then you can spend effort to narrow that interval (reduce uncertainty), if you choose.

Many things become possible when you let go of belief being all or nothing. We can act on 80% confidence, and learning from additional data while we proceed. Real life happens in the gray areas.