I’ve started occasionally listening to Rationally Speaking podcast, a production of the New York City Skeptics. What’s funny is that part of the reason I listen to it is that I get into arguments (in my head) with the hosts of the show, who are dedicated to the idea that rationality will lead people to better lives. One of the hosts, Julia Galef, has even started a Center for Applied Rationality to teach people to think more rationally and thereby improve themselves.

And I get that. Heck, I wrote a post eight years ago where I say that “one of the greatest problems facing this country right now is the lack of critical thinking skills. People don’t know how to evaluate information.” And I still believe that critical thinking is an important skill that more people should develop.

But I also have learned to recognize the limits of rationality in driving consensus and agreement. In particular, if two people are starting with a different set of assumptions, no amount of rationality will get them to an agreement – they are living in two different worlds. A mathematical analogy would be the difference between Euclidean and non-Euclidean geometry – the system of proof is the same, but you get different results if you change Euclid’s parallel postulate.

I’ve observed many instances of this over the years, where two people are trying to convince each other with logical, rational arguments, and are unable to do so because they don’t realize they are starting with differing assumptions. They are muttering “Why can’t you be rational about this?” but they need a common starting point or set of axioms before the rules of rationality can help. I’ve touched on this before in regard to the multiplicity of goals one can design a system for and how a religious system is optimizing for different goals than a rationalist system. That doesn’t mean things are hopeless when assumptions differ: Getting to Yes is all about working to shift people’s assumptions so that an agreement can be found.

I also think that rationality is often ineffective, despite being “right”. George Lakoff suggested in 2004 that the Democrats were making that fatal mistake – that “if you just tell people the facts, that should be enough – the truth shall set you free. All people are fully rational, so if you tell them the truth, they should reach the right conclusions. That, of course, has been a disaster. ” All the rational and well-constructed arguments in the world are not as effective as a well-constructed story in getting people to change their behavior, as described in Made to Stick.

So while I applaud those who champion the cause of rationality and critical thinking, like the Rationally Speaking podcast hosts, I think that reason is not enough (hence my mental sniping back at the podcast when I listen – to be fair, I’m setting them up as a straw man in this post). Even in a rational world, people will have different assumptions necessitating a discussion of what is truly axiomatic. And for all of our striving to be rational, it’s much more effective to convince people with a story than with a rational argument, because the story resets their assumptions and encourages their brain to fill in the blanks in a different way.

To tie this back to yesterday’s post on Principled Leadership, a fully rational approach to running a company would be having a strict hierarchy and process, with the reasons for each optimized decision laid out for employees. What I like about leaders modeling guiding principles is that it demonstrates a way of driving a common set of assumptions across the company, and providing stories that people can use to drive their own behavior. It may not be strictly “rational” or optimal, but it may be more effective.

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drive their own behavior: I heard a story at one training on purchase orders where Patrick rejected a purchase order for $2,000 because it hadn’t been taken out to bid and there was no way for him to know that Google was getting a competitive price. Let me tell you that every time I looked at a purchase order after that, I paid attention to whether Google was getting a good deal, no matter how small the purchase.