Desirism is Antiquated Social Contract Theory

The best way to understand derirism is that it is old-fashioned social contract theory before Rawls and Harsanyi came along. Classical social contract theory is simply morality based on self-interest. There are no morals. The only thing like a moral duty is the duty to pursue your self-interest in a rational manner. If it is in your self-interest to be rich then you "should" get an education and work hard. So forget morality.

Now imagine yourself in what philosophers call a state of nature. That means a world with no governments and no laws. Might makes right. If you wanted to you could kill all the men you meet and take their stuff. You could rape all the women you meet. Of course, someone who is bigger and stronger than you are may kill you and take your stuff! Then he might rape your wife, sister and daughters. No one wants to live in a state of nature. So people come together and form a government. Philosophers call this the social contract. The terms of the social contract will include laws against murder, theft, and rape. See? Atheists have morality without God. The pursuit of rational self-interest provides an objective set of moral laws. Christians ask, "Why is murder wrong without God?" and the answer is "because I don't want to be murdered - and neither does anyone else."

The problem is that the social contract assumes that everyone has equal negotiation power. In reality that is not true. Men are stronger than women so it is in their self-interest to make a social contract that oppresses women. Members of a warrior caste are stronger than farmers and laborers so it is in their self-interest to form a social contract that turns laborers into second-class citizens. Rich people can afford to hire warriors so it is in their self-interest to create a class-based society in which they are at the top. And members of a majority ethnic group can oppress members of a minority group so it is in their self-interest to form a social contract in which they enslave or oppress the minority group.

This objection is fatal. Modern social contract theorists like John Rawls created a Veil of Ignorance to get around the problem (John Harsanyi created a similar idea before Rawls). Behind the Veil of Ignorance we do not know the particulars of our lives. We do not know if we are male or female so we would not choose a social contract that oppresses women. We do not know if we are rich or poor so we would not create a class-based society. We do not know which ethnic group we belong to so we would not create a society that allows ethnic oppression (according to Rawls' version, people behind the Veil do know that they are not an unborn fetus, so they would choose to create laws that allow abortion).

Desire utilitarianism is simply social contract theory without a Veil of Ignorance. Thus it is in the rational self-interest for people to create unjust social contracts. How do desirists get around this? Magical reasoning called the turn the knobs technique. The gist of this technique is to consider a desire to enslave others. If we "turn the knobs" on this desire up in strength and prevalence then society as a whole will be worse off. People will be enslaved, fighting wars over slavery, and so on. But we "turn the knobs down" on the desire for slavery then people will be more peaceful and everyone will be better off.

The fatal flaw is that it take the perspective of society as a whole. Why should members of an oppressor group (the men, the warrior caste, the rich, the ethnic majority) count the desires of of the victim group in their calculation? They just want to have "the most and strongest" of their own desires fulfilled.

So what you tend to see is a bunch of arguments that don't even need desirism or any type of atheistic ethics. You see arguments that it always against your self-interest to be oppressive. You see arguments that the only way to justify oppression is with false beliefs such as 'God said to kill the infidels'. See here for a more detailed discussion.


The Prisoner's Dilemma

The number of atheists that refuse to accept the logic behind the prisoner's dilemma is large. The gist of the prisoner's dilemma is that it is good for society if everyone behaves morally (cooperatively), but it is in the self-interest of each person to act immorally (to defect). Thus people are inexorably driven to immoral behavior. One well-known and misguided way to solve the prisoner's dilemma is with the strategy of tit-for-tat, or something similar. More generally, people often point to the Folk Theorem for Repeated Games. In intuitive terms it holds that people can reach cooperative outcomes in repeated games. But that is not quite right. It actually holds that there are many different outcomes, and that cooperative outcomes are only likely with a small number of players and with information conditions much stronger than we get in the real problem. In other words, in the real world people have ample opportunity to be anonymous free riders.

Desirism cannot give a rational reason to not be a free rider. At most it only succeeds in establishing laws, social norms, and cultural values (see here). What you do when nobody is watching is still up to you. So sure, desirist founding fathers can create a world with the social norm of "let's praise people who don't free ride on society." But since we don't know who is free riding and who isn't, the social norm is empty. If in this atheistic Utopia people have rational beliefs aimed at the truth then they will also have the belief 'free ride whenever you feel like it if you have the chance'.