Scripture: 1 John 4:20-21 Series: 2020
Preaching on 1 John 4:20-21, the sermon uses game theory, John Nash’s equilibrium, and Albert Tucker’s Prisoner’s Dilemma to set up a contrast: the ‘rational’ move is mutual betrayal, but the Christian life is not lived in such high-stakes traps. John insists that claiming to love God while hating one’s neighbor makes us liars; the visible neighbor is precisely where love of the unseen God becomes real. Most of life consists not of dramatic dilemmas but of millions of tiny daily moments, each an opportunity to show love.
Illustrations: game-theory-nash-equilibrium, john-nash-beautiful-mind, prisoners-dilemma, always-wanting-to-stay-silent
May 2
“If anyone says, “I love God,” and hates his brother, he is a liar; for he who does not love his brother whom he has seen cannot love God whom he has not seen. And this commandment we have from him: whoever loves God must also love his brother.” 1 John 4:20-21 ESV
Game theory
John Nash, a beautiful mind
Albert Tucker created the game called The prisoners dilemma
Two members of a criminal gang are arrested and imprisoned. Each prisoner is in solitary confinement with no means of communicating with the other. The prosecutors lack sufficient evidence to convict the pair on the principal charge, but they have enough to convict both on a lesser charge. Simultaneously, the prosecutors offer each prisoner a bargain. Each prisoner is given the opportunity either to betray the other by testifying that the other committed the crime, or to cooperate with the other by remaining silent. The possible outcomes are:
If A and B each betray the other, each of them serves two years in prison
If A betrays B but B remains silent, A will be set free and B will serve three years in prison
If A remains silent but B betrays A, A will serve three years in prison and B will be set free
If A and B both remain silent, both of them will serve only one year in prison (on the lesser charge).
I am usually bad at these games. I always want to remain silent, but according to the Nash equilibrium, the rational position is for both prisoners to betray each other. There is a lot of math surrounding this.
If we say that we love God and we don’t love our neighbor, we are liars. This is how John puts it. Even more starkly, John points out that in our neighbor, we have the opportunity to visibly show love.
Most of life does not consist in prisoners dilemmas. Most of life does not consist in having a gun to her head, having to choose between faithfulness and disobedience. Life is instead filled with tiny choices that seemingly have a little to do with one another. Millions of moments each day to decide whether we are going to show love to our neighbor. Millions of opportunities.