I am surprised you haven't read it before, because when I read your comment I immediately remembered that essay haha.

For conscious bias a good test is if being exposed to new facts prevent you from changing your opinion on something.

For example, imagine I was a very big believer of full-blown libertarianism and I was exposed to very concrete evidence that say, for example, government run healthcare is both more efficient and cheaper than private healthcare[1]. Would I still be full-blown libertarian and try to put holes on the data or would I embrace that libertarianism doesn't bring good outcomes in healthcare[2]?

Unconscious bias is much harder though, in fact libertarians tend to be very much fueled by ideology than facts. One could say that unconscious bias is fundamentally the same thing as ideology.

Another example, like I mentioned before I am very much a pro human rights ideologist. So I am inherently against some things like eugenics, even though one could provide data to me saying that eugenics would lead to "better" outcomes in society I would still be against it on principle.

[1]: Personally I sympathize with most libertarian views, but I don't consider myself a libertarian. I don't think a full private healthcare system is good for example. And this is the core issue the essay brings out, being a libertarian is assuming an identity and it closes you off to new ideas.

[2]: it is very hard to have absolute evidence to anything, but one must be willing to look over their own pre-existing world view when analyzing information available. A certain level of suspicion of information is warranted, but if you can't get past that, your world view is essentially ideology.