Probabilities for decisions
Given information about an individual you can calculate probabilities for him/her making different decisions. If our universe isn't deterministic then it's theoretically impossible to get to anything other than mere probabilities.
If your brain are in configuration X then you aught to do Y with probability Z.
But then the question become, why do we have these probabilities in the first place?
Evolution will over time promote behaviour that is better in terms of survival and reproduction. This is why we strive to have sex and most of us want to have children, it's an innate drive that isn't going away.
Some people are against reproduction "antinatalism" but that is a self-correcting 'problem', over time it will become less prevelant since these people weed themselves out of the gene pool.
It is worth noting that what genes that are good will depend on environment, thus evolutionary morality will not grant us some grand absolute morality.
The environment will be affected by decisions made by animals (especially humans), political decisions we make will affect the evolution of humans even if most people prefer to ignore that fact.
Cultural survival of the fittest
Some cultures will naturally spread while other cultures will become increasingly less common. A culture can grow by reaching new people or by being transferred to children being born to said culture.
Cultures that promote fertility will spread naturally by causing higher birthrates among individuals that believe in said culture, furthermore people that are neurologically suseptible for said culture will end up reproducing more and thus keep spreading the culture even if it's unpopular among most people.
How easy it is for a particular culture to spread will depend on society and neurological factors. Some cultures will naturally appeal to people and gain popularit even though it's bad in terms of survival and reproduction, this will however die out over time.
Societal survival of the fittest
Weak societies will fall and be taken over by stronger societies.
Democratic societies tend to become weak and this cannot last forever, you can utilize weaknesses in democratic systems to slowly grab power, after that there will not be any more real democracy.
One way to measure how successful a society is to look at survival and reproduction (birthrate). The by far biggest factor limiting the birthrate is females unwilling to have even close to the max number of children.There are several brutal methods (baby quotas, females as property) to maximize the fertility rate among desired females.
13 is a good age for a female to start breeding, if she is finished breeding early that will allow her to enter the economy and be productive to society early. It's also easier to force a young females to have children since it will be difficult for her to flee or fight back.
We also need to have a strong economy so we can support all our children we forced females to have, this will also allow us to build a strong military. In order to build a strong society we need to be inclusive, not exclude people based on ethnicity, sexual orientation or gender expression. By attracting important individuals to our society we make it stronger.
Unless you are militarily stronger than all other countries on earth combined it's very important to build strong alliances to ensure you will come out victorious in the case of a world war. By winning the world war we will be able to dractically expand our borders and eventually rule over the entire planet.
Totalitarian social control is unavoidable
The amount of totalitarianism in a society has an equilibrium point. If you restrict the power of the government you end up with lower-level totalitarian control instead 303132
By weakening the central government you may end up with organized crime, parents having totalitarian control over their kids, sects, psychiatry, etc.
Ordinary "checks and balances" only change who has the power, by making the supreme court more powerful you make other branches of the government less powerful. By making it easier to impeach the president you simply empower congress at the expense of the president. If we allow citizens to instantly remove the rulers from power via a vote we just end up with more mob rule.
While you may dislike totalitarianism and try to fight against it all you are doing is moving the power somewhere else or making the current system unstable. By promoting libertarian values you will be able to weaken the ability of a government to exercise social control and this will make it easier for you to yourself gain control, you do however run the risk of the current rulers losing power to people even more problematic instead of you gaining control.
If we go too far when it comes to controlling people it will hurt the economy and make the government less popular. Weaker economy and less technological advancement means it will become more difficult for the government to effectively control people.
Implications of reincarnation being true
Consciousness having a continuation after death will have natural implications for our decisions and this will depend on neurological factors to a large extent determined by evolution. Humans will be more motivated to work towards a better future and thus we ought to do things that will improve our upcoming life experiences.
From evolution we have been shaped to value great sex and thus we will naturally desire to secure that for upcoming life experiences too and not just our current lives.
evolution will over time shape us to do what's best for survival and reproduction
It's actually not that simple. What's ideal for survival and reproduction will depend on environment and the environment will depend on decisions made by humans.
If being intelligent is better in terms of survival and reproduction then the average intelligence will increase over time even if said higher intelligence also leads to decisions not ideal in terms of survival and reproduction. Evolution cannot fine-tune human decisions to always to what's ideal in survival and reproduction, it's a crude mechanism which is why we have homosexuality and people killing themselves.
If reincarnation is true then humans will start believing in it given enough intelligence and intellectual progress.