Well if they have eyes and are not color blind, tell them to look up. (things people can rationally verify are obviously the easiest to make someone believe)
Now, if they are blind and we do not know them AND they do not trust us when we tell them it is, we should have someone they trust tell them that the sky is blue.
Why does trust help in conviction? Conviction is based on the risk/reward ratio that we calculate for believing something to be true. Given the fact that there is no real risk to believing it’s another color, and he knows we do not have much of anything to gain by lying to him, it is less likely he will not believe us.
On the other hand, if we ask him to give us $10 so we can get gas to claim our lottery ticket which we will give him $1,000 back. There’s going to be a much higher difficulty. The risk / reward ratio here is pretty poor. On the other hand if your friend says that, you know they are poor and a degenerate gambler, but they have not lied to you for years. Your reward ratio will win, and you’ll go ahead and take the action.
Next;
How do we convince someone that volunteering is a good way to spend a Sunday?
Well again, we just need to increase the perceived reward over the perceived risk.
For most people it is of course more difficult to get them to volunteer an hour of time versus watching a game of football. Football not only gives more stimulation, but requires less caloric output, thus our bodies motivation for that action is naturally higher given we evolved to maximize reward for the least amount of caloric use. (Some people are different and find more value in volunteering than spectating something they have no control over) of course, many people still want to consider themselves good people.
Of course if we offer a cash incentive, depending on the cash amount and depending on the financial, it adds varying degrees of rewards that could tip the scale.
How do we convince someone to devote all their money to a good cause?
Now it gets a lot harder. That is because the risk involved is… all financial security someone has, yet this action is done more than people think…. in someone’s will. Once someone is dead, there is no more risk to giving all their money away, besides the idea of leaving loved ones behind with less. Some wealthy people who understand the destructive nature of money will give their kids a fraction of their wealth (making sure they have enough to live a good life) but give the rest away. Hoping for the best positive outcome for their lineage and thus the world.
How do we convince someone that they should help everyone as much as they possibly can?
While this does exist, most people are NOT wired this way. The question of whether this is from nature, or nurture is of course a mix. But if we think about what variables nature/nurture really changes it returns back to this risk/reward ratio that exists in peoples’ minds.
Really our question is, how do we create the idea of maximum reward for doing good, and maybe even add some risk to not doing so. Obviously once you introduce a reward, risk is created as simply the lack of that reward, but as we have seen with historically widespread religions, they often employ the carrot (reward) and the stick (fear).
I like defining religion as a set of unprovable beliefs practiced with others in a network.
For example, in Christianity acting in faith of Jesus, and not sinning brings eternal utopia (literally heaven), and not believing brings you into eternal hell. Obviously if you have maximum conviction in this idea you are going to think twice about the risk of infinite hell that comes with stealing that candy bar.
On top of that, governments aligned with a religious faith often added environment factors to add even deeper risk to not believing, and threatening the beliefs of others was punishable by death. T Founding of America was caused partially by the people who felt oppressed from free thought in Great Britain, who would literally KILL you if you tried preaching ideas that did not put Jesus Christ as the savior.
Nowadays, the conviction in these historical risk/reward frameworks for doing good are wavering, and it begs the question if these religious frameworks for eternal reward in heaven being wrong? Is the idea of good karma real? Is there an eternal penalty for not living up to your full potential?
At the very least its mutually agreed upon this long term framework of reward is good for society. It asks people to become better, to hone the internal calling to be a source of value for the world. It asks individuals to look past themselves and instead look at the greater whole that they are a part of.