First, I had a conversation with someone who had said that Libertarian Free Will enabled us to make promises and keep them, because we are the ones who determine whether or not we will keep our promises. In response, I said (slightly edited):
Except that you're not the one who determines that. Even on your own terms, you are only part of what determines that. For instance, if you promise to meet someone at 5, you might be delayed by traffic. The car might break down. You might run out of gas. You might have a heart attack en route. As James says:The response that I received back was that there were two different types of promises, and some of them could be kept completely under our control. The example given was that a person could decide to forgive or not to forgive someone. Ultimately, the claim was, you could make a promise when it “only includes your own actions and efforts” because those do not need “Lord willing” with it.
Come now, you who say, “Today or tomorrow we will go into such and such a town and spend a year there and trade and make a profit”—yet you do not know what tomorrow will bring. What is your life? For you are a mist that appears for a little time and then vanishes. Instead you ought to say, “If the Lord wills, we will live and do this or that.” As it is, you boast in your arrogance. All such boasting is evil (James 4:13-16, ESV).Since I know you believe the Bible, and since I know you think the Bible teaches LFW, then clearly you should agree that even under LFW, you are still not the one who determines whether or not you keep your promises.
I responded by pointing out that everyone is connected in an intricate web, and even the decision to forgive or not to forgive another person can have drastic consequences. Take a married couple. If a husband chooses to forgive his spouse for a sin she has done, their relationship can blossom and grow; if he chooses not to forgive her, then the relationship can become bitter and lead to divorce. This one choice to forgive or not to forgive obviously includes more than one person’s actions and efforts, because everyone is connected. Indeed, it is easy to imagine a scenario where the difference between forgiving and not forgiving a spouse could be the difference between a future child existing and a future child not existing. In the case of a divorce, then presumably both spouses will have other relationships too. Supposing both remarry, the person they remarry are now married to people they otherwise would not have been married to. The ripple effect can be enormous. What if the child the couple would have had would have cured cancer? Now millions of people die who otherwise would not have died.
Because of the intricate, delicate web of connectivity between all human beings, it is impossible for us to say that any choice we do is made in isolation. Which brings me to the second aspect.