The things that happen between people’s ears are difficult to study. Similarly, the actions that we take and the symbolic gestures that we communicate to the people around us are also difficult to study. We often and easily perceive the social signals of otherwise mundane activities, but they are nearly impossible to quantify systematically beyond 1^st person accounts. And that’s me being generous. Part of the reason that these things are hard to study is that communication requires both a transmitter and a receiver. One person transmits a message and another person receives it. Sometimes, they’re on slightly or very different wavelengths and the message gets garbled or sent inadvertently and then conflict ensues.

Having common beliefs and understandings about the world help us to communicate more effectively. Those beliefs also tend to be relevant about the material world too. A small example is sunscreen. Because a parent rightly believes that sunscreen will protect their child from short-run pain and long-run sickness, they might lather it on. But, due to their belief, they also signal their love, compassion, and stewardship for their child. A spouse or another adult failing to apply sunscreen to a child signals the lack thereof and conflict can ensue even when the long-term impact of one-time and brief sun exposure is almost zero.

People cry both sad and happy tears because of how they interpret the actions of others – often apart from the other external effects. Therefore, beliefs imbue with costs and benefits even the behaviors that have seemingly immaterial consequences otherwise. We can argue all day about beliefs. And while beliefs might change with temporary changes in the technology, society, and the environment, core beliefs need to be durable over time. Therefore, if this economist were to recommend beliefs, then I would focus on the prerequisite of persistence before even trying to find a locally optimal set.

Here are three inexhaustive criteria for a durable beliefs: