Regarding Willpower: I am glad you seem to have connected with the idea that one of the principle adaptive functions of religion may be to effectively increase an individual’s willpower, that is, the ability to resist the temptation to go for short-term small rewards especially in cases where such moves interfere with projects aimed at long-term large rewards. Gaining willpower, as defined above, is a developmental emergency for every human if they are to have any chance of doing well in maximizing their lifetime inclusive fitness. Genetic systems and cultural systems that help speed up the process are likely to be under strong positive selection in all human groups.
It is easy to see that the basic human social system of “complex contractual reciprocity” cannot really function if members of the group behave like undisciplined stock traders. Contractual reciprocity does not work if people are preoccupied with cashing in too early when there are some small profits to be made or selling to early when the stock starts going down. If you translate this into human relationships it would negate the idea of any kind of trusting friendship or loyalty. This would make for a very weak group if not for chaos. So, as I think you realize, religions offer supernatural long-term large rewards in connection with teachings that you can only attain them in, in this life or an afterlife, if you develop the willpower to focus with discipline on attaining, usually through sustained cooperative behavior, large rewards based on long-term projects in this mortal life. Many sins turn out to be behaviors that are aimed at attaining short-term small rewards.
You ask what kinds of factors or forces would override the limbic system. I believe this is identical to asking what would override the regulatory mechanisms in your brain that control your heart rate. The mechanism’s that the late Gerald Edelman called “value systems,” which guide corticothalamic neurodevelopment on developmental time scales and which heavily influence corticothalamic activity moment to moment, essentially in real time.
There may be meditative techniques or other kinds of esoteric exercises that give our giant cerebral cortex more freedom to integrate information beyond what normally would be allowed, in a given socio-ecological context, by the limbic system. That is an empirical question which really begs for an answer. After all, for all we know certain of these spiritual exercises, even though they make us feel good, just might increase the degree to which so-called “higher” cortical information processing mechanisms are enslaved by stark Darwinian “values” inherit to the limbic system.
In most cases, for the vast majority of people, there isn’t going to be any overriding of the limbic system. Fortunately that might not need to happen! The limbic system cares about getting fitness-enhancing needs met effectively and efficiently. If we train our brains, our minds, possibly with the help of our religion, to get our fitness related needs met by engaging in behaviors that also benefit others, prosocial and even biophilic behaviors, compassionate behaviors, the limbic system can learn that such methods work. It will then endorse them, more and more, as we build up success rate of such beneficent systems of behavior and relationship. Reciprocal altruism is all about establishing social contracts in which all parties involved gain some net benefit. A solid history of reciprocal altruism within a group carries with it the enormous side benefit of increasing the level of commitment amongst group members so that they can deal better, more cohesively, in the face of outgroup threat or other hardships. To the degree that religious narratives and stimuli can drive us towards getting our needs met in ways that also benefit others, then those religions are effectively getting the limbic system on board to endorse beneficent and compassionate behaviors among social partners.
There is still a problem though, and it is a very big one. For the most part, when humans develop strong willpower and enjoy its major benefits, the altruistic behaviors involved are usually mainly directed towards in-group members or close allies of the in-group. Our altruism tends to be distributed in a very parochial fashion. This way of distributing altruism, in such a contingent manner, based on degrees of genetic relatedness and degrees of trust current through the history of interactions entailing reasonably fair reciprocal altruism, still allows for intergroup hatred and conflict. Somehow we have to culturally and probably genetically evolve beyond this increasingly unsustainable style of coalitional psychology. This is a very tall order, especially when you consider that if we are to survive we have to extend our ability to behave compassionately not only towards other humans from other groups but also towards the rest of the biosphere. We have to sharply decrease the contingency both of our pro-sociality and are biophilia.
This will probably require a program of intentional evolution based on genetic and epigenetic engineering of our own species, using the precise genetic editing technologies that are now emerging, on ourselves. Such a system of intentional evolution, given the nature of human religiosity, is probably much more likely to be successful if it is guided by rigorous hard-core science and secular public discourse. But, so far people are refusing to talk about doing this, and religious people may be the last to be willing to allow themselves to give it serious consideration, even though it is probably our only chance not only to save ourselves, but to attempt to seriously minimize, at least in the long-term, the suffering of all sentient beings on our delicate little Earth.
The self-deception, adaptively subjective “conscious” dream world, strategically labile morality, and consequent behaviors that our species-typical naturally-selected genetic constitution drive are responsible for the continuing decimation of the earth and the misery and deaths of thousands of people every day. Sometimes it is frightening to act. But sometimes inaction is much worse. — PJW