If common sense, and its associated logic, could answer the questions it poses, there would never have been a need for philosophy, or for much of science. The classic philosophical questions like “where did everything come from” cannot be answered by common sense, and therefore the answer, whatever it is, must be crazy, in common sense terms. To take an analogy, mathematicians could not answer every question in terms of integers, the counting numbers of common sense, so they had to invent fractions, and then real numbers, and eventually complex numbers, which include the notoriously crazy “imaginary” numbers. And then there is physics…the subject that gave us, thanks to Wolfgang Pauli, the phrase “not crazy enough to be true”.
Instrumentlal rationality and epistemic rationality aren’t the same. Epistemic rationality seeks to maxmise knowledge, truth and consistency. Instrumental rationality seeks to maximise efficiemcy, gain and personal utility. One area they come apart is signalling, the implicit and explicit ways we tell others what kind of person we are. The instrumentally rational way is to signal is to maximise your utility by sending out agreeable signals to whichever individual or group you need something from. This Vicar-of-Bray style behaviour will lead to your making highly inconsistent statements in the limit. If you want to signal sincerity, you will need to believe them too.So you will end up with inconsistent beliefs. So,IR+signalling is inconsistent with ER.
However, all this assumes you won’t be found out. If you are scrutinised, in different siutations, by someone who cares about consistency, the benefit of inconsistent signalling vanishes.And noone is scrutinsed more than a politician in a healthy democracy. People read reports of politicians contradicting themselves and being inconsistent, and infer that politicians are unusually hypocritical. But absence of evidence is not evidence of absence The ordinary persons hypocrisy is not publicised becausd the ordinary person does not have reporters following them round. The ordinary person typically moves in a number of fairly disjoimt circles –the workplace, family, same-sex friends and so on — signaling different loyalties to each. The existence of Chinese walls is even humorously acknowledged: “what happens in X stays in X”. Inconsisten.cy reaches a peak when communicating with completely unconnected individuals and groups. My go-to example is a telesales operative Iwho would ring various people during the crude of a day and agree with every word they said. Her customers were of course unknown to each other and in no position to compare notes,.