There are several elements here. First, most people are not rational, and they can't be motivated by rational deduction. Most people simply do not have the inte

There are several elements here. First, most people are not rational, and they can't be motivated by rational deduction. Most people simply do not have the intellectual horsepower to overcome their emotional perspectives and rationalize themselves into good decisions, even when the essential data is present. This invalidates "just be rational" as a practical solution to social welfare. Second, the essential data is rarely objective or complete. There are very few datasets where a subjective value judgment on some information can be avoided; if you incorrectly devalue some data, your "rational decision" can turn out to be very problematic indeed. So not only are most humans incapable of performing basic rational deduction, they also often lack the perspective necessary to adequately value a subjective dataset, where "adequate" means interpreting it to be compatible with general social cohesion and happiness. The tried and true traditions of the previous generations of a successful society may err in some smaller things, but in most things, they will be reliable. Young adults (< 50) often lack the maturity and perspective to properly understand the decisions they're making. They'd do well to listen to their elders and try to learn from them. All of this culminates in "religion" or something very close to it, and it's essential to social stability. If you don't provide one, a replacement will automatically generate. People will find and adopt a belief system as absolutes. You can see this in the "secularist" society of today, that adopts what they perceive to be "scientific consensus" as effective religious tenets, or in the "social equality" segment that adopts their interpretation of "diversity and equality" as effective religious tenets.