Outside view/counterfactual exercise. You have a cause, say global warming, which you think so important that even a small change to its odd of success trumps the direct moral impact of anything else you can do with your life. E.g. you believe that even an extra dollar of funding for alternative energy is more morally important than saving a human life (given that the person has a net 0 carbon footprint). However, you are open to the possibility that there is an even more important cause that trumps yours to a similar level. You also know that there have historically been people that thought their causes were as important as you think yours is and turned out to be horribly wrong, at least from your prospective e.x. the Bolsheviks. How much do you focus on directly contributing to your cause vs contributing to public goods, not defecting in prisoners dilemmas, and other conventional do gooding?