Mercy, Justice, and Mars

Mark Watney was stranded – on Mars in a rather barren environment. The image above (Credit NASA/JPL-Caltech/MSSS) from the Mars Rover Curiosity can be found along with many others at the NASA Website. Mark Watney, for those who don’t know, is the major character in a book and movie The Martian. Stranded alone on Mars, he has to figure out how to survive and communicate with Earth leading to his rescue. It is an enthralling story. Andy Walsh in his new book Faith Across the Multiverse uses Mark Watney’s adventure as a framework to explore a number of biblical ideas including the relationship between justice and mercy. Math plays a big role … Andy reflects on equations as the poems of math.

Poems are the most compact, densest forms of language and writing. They use rich symbols to convey layers of meaning in a few words. All of that can make them challenging to read and understand at first glance; one must decipher what each symbol represents.

In other words, poems and equations take a long time to read because they are information dense. Every word or symbol is meant to convey a large number of bits. As a result, ideas are expressed compactly and elegantly. But the reader senses that they are making little progress because decoding and processing all those bits takes time while only a small physical space has been traversed. (pp. 46-47)

In order to survive on Mars, Watney has to optimize the variables to have enough food and enough fuel to rendezvous with ship coming to retrieve him. Multivariable optimization problems are mathematical problems. Linear regression – fitting data to a line – is a simple example. In his book, Andy Walsh goes through a number of illustrations of the pitfalls in optimization problems.

What does this have to do with justice and mercy? There is a tension in the Bible between God’s justice and his mercy. There is also a tension between our calling to pursue both justice and mercy. Rather than seeing this as a conundrum or a conflict, it may help to view it as an optimization problem.

Another notable feature of these values we are called to optimize is the tension between some of them. If we were only to maximize justice, there would be little or no mercy, while maximizing mercy would yield very little justice. In mathematical optimization, it is common to have multiple constraints. The optimal solution across all of them might not correspond to the optimal solution for just a single constraint. In our rocketry example, maximizing just the length of the mission would call for sending far more food, but the additional constraints on total rocket mass once we take fuel into consideration mean we have to send less food than we might otherwise choose. Similarly, the Bible calls us to balance justice and mercy rather than purely optimizing just one or the other. (p. 59)

Although it is convenient to connect God with justice and Jesus with mercy, this misses the point. God exercises both justice and mercy in his dealings with with his people in the Old Testament. The laws sometimes seem harsh – but mercy crops up time and time again. The book of Jonah may be something of a parable to help us think about God’s justice and mercy. In particular God’s mercy in response to repentance. Jonah is unwilling to accept the fact that God is merciful – even after he himself is shown mercy. (See my post a few years back Forget the Fish Already!)

Likewise, Jesus stands for both justice and mercy. Andy Walsh gives a few examples:

Jesus stands up for justice as well as mercy. He cleanses the temple courts of merchants who are exploiting the poor (John 2). His teachings on anger and lust, holding them up with murder and adultery, are radical in their severity (Matthew 5). He also demonstrates how justice and mercy can be served simultaneously. When he spares a woman accused of adultery from stoning, he is showing her mercy while also standing against the injustice of prosecuting her alone (John 8). (p. 60)

These are running themes in the Bible, the tension between justice and mercy as Israel repeatedly turns away from God’s path in each generation. Walsh notes that “in Luke 15, Jesus tells the famous parable of the prodigal son, a personal version of the same archetypal story.” (p. 64) This is the elevator version of the biblical story.

We worship a God who in his wisdom, optimally practices both justice and mercy. We are called to pursue the same optimization in our dealings with others.

If you wish to contact me directly you may do so at rjs4mail [at]

You may also comment on Mercy, Justice, and Mars at Jesus Creed.

This entry was posted in Christianity, Science and tagged . Bookmark the permalink.