|Waterfall - M C Escher - from Wikipedia|
Suppose humans are not always rational. It isn’t a wildly improbable assumption is it? We just have to look around the world, consider the things that happen which rational beings wouldn’t get involved with. I’ll not labour the point because only an irrational person would disagree.
So what are the consequences? Well of course, as we all know, it depends how rational or irrational people are, but there’s no measure of irrationality, so we can’t say exactly.
We only identify irrational behaviour when we come across it, either in real life or in fiction. But if you come across it in real life and tell an irrational person they are behaving irrationally, they don’t understand why.
Because if they understood you they’d be rational.
The same logic applies to a society as to the individual. An irrational society can’t tell it is has become irrational and can’t be told why or do anything about it. This is a simplification of course, but enough I think to establish a point of exploration.
So in a social sense, irrationality could become something like an epidemic. It could become contagious because human behaviour is largely imitative. Of course one could say the same thing about rationality, but not quite.
There is a difference.
One aspect of rational behaviour is where we identify irrational behaviour and avoid imitating it. There is no corresponding avoidance mechanism for irrational behaviour.