Some things are up to us, and some are not. The first thing that is up to us is assenting to a proposition. Also up to us are the criteria that we decide to assent or decent, or withhold judgement on that or any proposition. Are those criteria truth or utility? If utility, for us or for others. If it is truth, our truth that we can develop from first principles or what we have been told, as truth, by our holy guidance?
Ultimately, this is a question of how does the data flow in our thinking process and what are the criteria of our decision making process, what ever that might be. We all have a decision making process, and these can be described, have been described by others. We all collect data and compare that data to criteria, and based on some method, make a decision. Or not. Some just refuse and sit there... for a while.
As youths, we often accept that which we are told by elders as being the truth. That is fine as long it is true or has positive utility, positive value to society to believe. One problem comes when what we are told is untrue and does not have a positive outcome on the whole society, only on parts. It may have a positive outcome only for the individual, and that is the birth of the sociopath and/or psychopath. The time of unlimited population growth must end, and that must be also accounted for in our belief system. We must each, for ourselves, reevaluate all that we have been told to believe.
The Islams have a problem. They have been told not to think for themselves, but to follow, what it turns out to be a bloody plan to kill the non-followers. Some are less true followers, and do not follow the Qur'an, and call themselves peace loving, yet the Qur'an says kill the non-believers, and this is a religion of peace within the surviving people, not with the neighbors. Old Islam does not preach peace with others, only peace inside their group. Oh well.
Peace with ourselves comes with knowing that we are responsible to know ourselves, and decision style and criteria. If we think it is permissible to do anything, as long as it benefits ourselves, or our fortunes, we may be less than human. If we only do that which we can derive from first principles, like we are all here to cooperate to provide a flourishing society, or treat others as we would like to be treated. Truth, derived from first order principals must be more right than things derived without reason. When we can lay out the reasons for our actions, at least we justify it to ourselves.
I would greatly appreciate hearing your views on this subject. I know that there is great diversity and little uniformity, but then what do I know?