Does Jesus' Fruit Tree Illustration Disprove Libertarian Free Will?

“Watch out for false prophets. They come to you in sheep’s clothing, but inwardly they are ferocious wolves. By their fruit you will recognize them. Do people pick grapes from thornbushes, or figs from thistles? Likewise, every good tree bears good fruit, but a bad tree bears bad fruit. A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Thus, by their fruit you will recognize them.” – Matthew 7:15-20

I've heard some Calvinists use Jesus' fruit tree illustration in Matthew 7 to support compatiblism (the view that we can only act in accordance with our strongest desire or in accordance with whatever nature we have). They'll say that Jesus taught that we can only act in accordance with whatever nature we have, and he used fruit trees to illustrate the point. In fact, they'll emphasize the word 'cannot' at the end of the illustration "A good tree cannot bear bad fruit, and a bad tree cannot bear good fruit". They'll say that a good tree simply cannot up and choose to bear bad fruit just as a bad tree cannot just suddenly decide to bear good fruit, but each tree can only bear fruit in accordance with the type of tree that it is (i.e its nature). They'll say that this type of illustration makes perfect sense on compatiblist freedom, but not so much on libertarian freedom since on libertarian freedom, we have the ability to choose between the alternatives good and evil, and whichever one we choose, we did not have to make that choice, but could have chosen the other alternative. Just as good trees only bear fruit, and only bad trees bear bad fruit, so can human beings only act according to their nature. Once a man is regenerated, he becomes a different tree and starts producing different fruit (i.e the fruits of the Spirit mentioned in Galatians 5).

What should Christians who believe in libertarian free will (Arminians and Molinists) do with this argument? Are they correct?

I don’t think these implications follow. According to my interpretation of the passage, the point wasn’t that trees (humans) are incapable of acting differently than their nature. Rather the point Jesus was making was that it is impossible to conceal your true colors for any great length of time. Wolves look like sheep. Bad trees look like good trees, but eventually, when the harvest time comes, the tested fruit will reveal the nature of the tree. You can’t hide who you truly are forever. Eventually something you say or do will give you away.

But what about Jesus’ statements that a good tree cannot bear bad fruit and a bad tree cannot bear good fruit? Isn’t this saying that people cannot act except in accordance with their nature? Well, first off, if you interpret the passage in this way, you arrive at the same bizarre conclusions. If the bad tree/nonbeliever only does evil then how do we explain the real and good actions that even nonbelievers sometimes do? You end up having to reinterpret all of their good deeds as actually bad deeds with some peculiar rationalizations. But it gets even worse if the good tree represents the believer. If the good tree only produces good fruit then it would follow that the believer can only do good actions! Restated, if the determinist is right about the trees only producing good or bad fruit, then with regard to the believer it would mean that Jesus was teaching sinless perfection/that the believer only and always does good and is incapable of sin. That completely flies in the face of other bible passages as well as common experience. Since believers still sin, does that mean that the believer has two natures that necessitate their good actions and their sins?

Secondly, we often say that we cannot do something when what we really mean is that we should not or would not do something. For example, if I say “I can’t eat 3 large pizzas in 1 setting!” that would be a statement of incapability. I would be saying that I am physically unable to eat 3 large pizzas in 1 setting. While I can certainly pack away 1 large pizza in a single setting, I cannot pack away 3. So that is a statement of incapability. However, what if I said “I can’t tell my girlfriend that her dress is ugly” that is not a statement of incapability. I am perfectly able to tell my girlfriend that her hypothetical dress is ugly. What I mean by “I can’t tell her that” is really “I won’t tell her that”. I’m saying I refuse to tell her that. Or if I said “I can’t stay up late. I have to get up early tomorrow” I’m saying not that I am unable to stay up late but rather I “shouldn’t” stay up late, or that I’m unwilling to stay up late.

In the same way, Jesus could very well be saying that born again believers won’t consistently bear bad fruit (though they may on occasions). They will refuse to bear bad fruit because they freely choose to adhere to God’s commandments. Generally, you’ll see good deeds and behavior from them. With nominal Christians, you’ll consistently see bad deeds and behavior from them rather than good. You’ll witness a lifestyle characteristic of a non-Christian rather than a Christian.

Moreover, while real live trees are indeed incapable of producing fruit other than what they do in fact produce, people are not trees! The problem with taking Jesus’ tree parable so woodenly is that all illustrations and analogies break down at some point. The point of the illustration was to show that certain types of people live certain kinds of lifestyles, and you can discern who is who depending on what they say and what they do. That’s all that the tree illustration is trying to communicate, nothing more. You push the illustration too far if you infer that “Well, trees can’t freely choose what kind of fruit they produce, so humans must not be able to choose what kind of fruits they produce either.”

It’s not surprising that Calvinists would take the tree analogy to infer compatiblism as they often take biblical metaphors and word pictures, and push them beyond what they were intended to communicate.

Moreover, verse 15 tells us that we’re not just talking about Christians in general, but rather false prophets. Jesus is saying we can determine who is and is not a false prophet by their fruits. Now, some actually dispute the meaning of fruit here. Some argue that the false prophet’s fruit is their teaching (i.e doctrine). In other words, “you will know they are false prophets because of their false teaching.” Others have said that the fruit is the lifestyle that they lead and the lives that they encourage their followers to lead (as I’ve been presupposing this entire post). In other words, you will know them by their ungodly lifestyle and the ungodly lifestyle adopted by their followers. What is the fruit that our Lord speaks of here? Is it the teaching, or the life? It seems plausible to me to think that it’s both. I don’t see why the two views have to be mutually exclusive. It is possible that the fruit of a false prophet is both heretical theology as well as an ungodly lifestyle.

In Conclusion

This passage doesn’t disprove libertarian free will at all.