"There are so many cognitive biases that I'm pretty convinced humans almost never act based on reason. But then that's what makes us who we are. Why try to be something we're not?"
Neil is right. Again, from ConCom, we spend most of our time in our Monkey Brains. Being fully in the human brain is rare. And it is probably just as much a Dunning-Kruger as anything else-- some of the least rational people I know insist on their rationality. Conversely the most rational people I know are always questioning themselves. In my opinion, the expert is not the one who can tell you what is right and what is wrong. The expert is the one who can argue from any side, explain why he or she believes that one side has more merit and is able to say, "Of course, I could be completely wrong because..."
Also remember that reason is a discipline. It is not an intention or an attitude. Declaring yourself to be reasonable or logical does not make it so.
From my current work-in-progress:
Understanding experimental design and logical fallacies are just two parts of a much greater skill. That skill is critical thinking. Like reading people, it is not binary. It is something that continually improves with practice but will never be perfect.
People are by nature, far more emotional than rational. Rationality is actually a rare and precious skill. Even more, survival, self-defense and the crimes that necessitate them are emotional hot buttons....
One of the biggest hurdles to true critical thinking is that we have a presumption of our own objectivity. We can look at all the people around us making stupid decisions clearly based on ill-informed emotion, and never, ever notice that we do it just as much. To actually be good at critical thinking requires a willingness to doubt yourself. Ideally, an ability to find the joy in error-- you only truly learn when you are wrong. Searching for your own blindspots is a life-long endeavor.
There is no point at which one can say, "I am rational. I am objective." It is a skill. Something you get better at through dedicated practice. Like the Stoic idea of good, you couldn't get there. You work towards it. That's virtue.
It is really easy to analyze other people's positions, statements and stances and point out the logical fallacies, the facts they choose to ignore, and declare them irrational. It makes one feel superior. It's a trap.
The valuable skill and the discipline is to do the same with yourself. Know the logical fallacies well enough that you catch yourself when you use them. When you catch yourself shunning a source or a point of view, dig down and find the reason. And you have to learn to differentiate between your own excuses, justifications and the real reason. (Hint: justifications and excuses don't predict future choices.)
To reject reason because reason will never be perfect is to cut off your left hand because it will never be as dexterous as your right (see what I did there? Multi-lingual pun.) Or to reject being good because no one is perfectly altruistic. To reject all learning because we never know the universe...
Reason is a tool, and it is a tool that improves with practice. Further, it can sharpen and assess all of your other tools. It can be a check on your own integrity. Never perfect, but it makes things better.
And any time you reject a tool, you reject part of your own agency