I see that the useful lie argument still has some support even among people on this site. The one where religion is seen not as really true, but as a useful tool for regulating public opinion and behaviour. Especially of course, when used in the hands of those, who regard themselves arbiters of morality.

Yet even to my limited mind, there are at least three failings with the idea.

Firstly. By using religion and setting up fake sources of authority such as divine beings, old books, supernatural revelation, traditions, or even guru based wisdom, as your justifications. You create a lie friendly culture, where sceptical thinking is discouraged, and the sources of fake authority set up for one thing, can be picked up and used by the anti-social, for quite others. Such as where cultural Christianity, is picked up by racists and fascists etc. and its authority and its preconditioning of people to accept things like belief in the authority of literature over other media. ( The Bible becoming Mein Kampf . ) While the acceptance of high levels of cognitive dissonance is encouraged, to help with the manipulation of the public mind, which surely can not be done without damage to public thinking in all other spheres, where sloppy habits are encouraged in one. The lie may have the best of destinations in mind, but when once you start down the path of fallacy, then all other lies are supported, and there are many branching points to other falsehoods.

Secondly. You are sure to be found out. Lies in the end are always seen through, to some degree, and when that happens, then even the good ideas you may be trying to propagate with their help, become tainted and devalued by association. You then find yourself in the position of the parent who used the bogey man to enforce their rulings, to avoid having to explain the logic of them. Then finds in the end, that they have a rebellious teenager, who now understands the trick, and they have lost all credibility. For example it is no accident, that if there is a rise in immoral hedonism in the world today, then it is in part, because morality itself is now, wrongly seen, by many hedonists, as belonging to a primitive and now scorned religious past, instead of to the world of reason.

And thirdly. There is a horrible cost to using fallacy, however good the intent. Because those who attempt it, are inevitability, forced into having to defend their falsehoods . They find themselves having to accept high levels of personal cognitive dissonance, and are often forced into using the lowest of cheap propagandist tricks and debating techniques, because no better ones can be twisted to serve fake evidence. So that due to the long abuse it suffers, they begin to lose their moral compass, their natural moral instincts shrivel, and begin to look dishonest or just plain sleazy to other people. Who may then ask the obvious ad hominem, questions. What form of ideology creates such people or needs the support of such people and such methods ? And what makes those willing to use fake authority the best choice as moral arbiters ? So that the propagators of the useful lie, end by becoming themselves in person, the most obvious reason to distrust the very thing they set out to promote.

All of which is apart, from the pure snobbery, cowardice, arrogance and misanthropy, of the position in the first place, which regards all other humans as forever beyond reason, or the benefits of education and self improvement. A level of snobbery hardly respectable in the nineteenth century let alone the twenty first. While it often does in the end become no more than a self fulfilling justification for bad, failed and underfunded education, social justice and law.