Castles on the Rhine
One of the highlights of a Rhine River cruise occurs on the middle portion of the tour. As the river meanders back and forth down the valley between France and Germany, castle after castle appears on the heights looking down on the aquatic highway of commerce and travel. The soaring towers and arched walls are beautiful, ancient relics.Castles protected the domain of a duke or lord, allowing him to command a region of the valley. They offered protection during an attack from his enemies. The predecessor of the castle was the wooden palisade, providing a reasonably sturdy fort against the attacking enemy. Until the enemy came with battering rams and flaming arrows. Like the third little pig, the fortification designers turned to brick and stone as a stronger material than wood. The duke could rely on stone bulwarks to keep him and his subjects safe.
How safe was the castle? Though the stone could withstand flaming arrows easily, it still had certain vulnerabilities. If the enemy couldn’t penetrate the walls, they could go over them. They could run up to the wall with ladders and quickly climb to the top. Even with defenders shooting at them, a large enough force could eventually surmount the walls.
Even then, engineers realized that any single point of failure was not acceptable. This led to the invention of a moat to surround the walls, slowing down any would-be invader sufficiently to repel the attack. The necessity of entry and exit created a permanent structural vulnerability—a weak point that required further innovation. The invention of the portcullis helped fortify this gap. The portcullis was a metal grating that could be lowered into the archway to prevent entry.The degree of safety all depended on people. The lord of the castle had to trust that the architect planned it well and that the builders constructed it with proper materials and technique. One slipshod use of materials could weaken a wall, making it vulnerable. He had to trust the guards who stood watch over the gates at night. One bribe might let the enemy slip inside during the night watch. The lord of the castle would be making a grave mistake to believe that the physically imposing structure by itself guaranteed his safety. He would be putting his trust in something that seemed reasonable and tangible, but ultimately the wrong foundation on which to place his trust.
Stone bulwarks provided a tangible sense of security in the past. Even further in the past, humans trusted in technology to protect them, such as military grade carts and horses. But then as now, perhaps their faith was misplaced. “Some trust in chariots and some in horses, but we trust in the name of the Lord our God.” (Psalm 20:7) Let’s take a closer look at our own personal safety in light of scripture.
Personal Safety and Scripture
My home is my castle; my body is my temple. These are metaphors of physically imposing structures that imply stability and safety. We all want to feel safe in our own homes and feel safe from bodily harm.
In contrast, the Bible points us away from ourselves. Even though self-preservation is our natural instinct, the urge to preserve ourselves can lead to sin. Pursuing our own safety can lead to the sin of pride by putting ourselves before God and others. It can lead to the sin of idolatry by putting something else powerful in place of God to give us (the illusion of) safety, such as money, power, or technology. The problem is not the desire for safety by itself – the problem is who or what we trust to make us safe.
Safety is most often described in scripture as finding our refuge in God. God tells us to change the direction we turn for self-preservation. Instead of focusing on ourselves or earthly things, we must focus on trusting him. I suspect this is one way of honoring the greatest commandment, to love God with all our heart, soul, and mind. That is, love is not just a feeling of our heart, but the trust we place with our mind.
Engineering a Parapet: Safe Designs for My Neighbor
The second greatest commandment gives us another twist on how Christians should think about safety. Our urge for self-preservation was turned upward to trusting in God, now it is turned outward as well. The commandment to love our neighbors as ourselves means that we must preserve our neighbor as much as we preserve ourselves.
Engineers can do a lot to preserve the safety of our neighbors. We can improve their physical well-being and reduce their risk of harm through the technology we design. We can also be mindful that our technological products themselves could harm our neighbor. I have mentioned this passage in a previous blog “Running with Scissors” but it is worth repeating here: “When you build a new house, make a parapet [low guard wall] around your roof so that you may not bring the guilt of bloodshed on your house if someone falls from the roof.” (Deuteronomy 22:8)Clearly we are responsible for the health and welfare of our guests. If our belongings, including our technology (such as rooftop terrace) cause harm, we are accountable. As engineers, we should think of our designs the same way: if they cause harm, we take responsibility and work to reduce that harm in the future. Building a higher parapet is building in a safety factor.
Besides concern for everyone using our technology, we engineers can also give extra attention to our neighbors who are most vulnerable to harm. In the Old and New Testament, we repeatedly see that God has a special heart for the defenseless, destitute, and unwanted among us, such as widows, orphans, and foreigners. Most of us live in places that have a capitalistic economy, which drives technology design to cater towards the rich. While capitalism can be very efficient and often fosters stewardship of our resources, it can also devalue the vulnerable who are usually short on cash.
Thus, it might seem that the only way we can design for the vulnerable is when we pursue it as an altruistic work of volunteerism. It is true that there are many opportunities for engineers to serve their communities near to home or around the world. However, I wonder if we could think deeper, based on a presentation I once heard at the national conference of the American Society for Engineering Education (ASEE). The presenter pointed out that billions of people in the world today live on less than a few dollars a day. He noted an opportunity for development focused on very low-cost technology that could still be attractive to business because of the huge scale (billions of customers). Volunteers might be able to address poverty in a single community. By creating a technology along with a business plan, helping the poor could be scaled up to global proportions. He challenged the audience of engineering educators to inspire their engineering students to think along these lines. I think we too can think along these lines for addressing the safety of our vulnerable neighbors. That is, in order to provide safety at scale, we need to be particularly ingenious about developing technology with a business value. We need to incentivize mass production to get to global scale.
I suspect our Christian witness speaks most clearly through actions that show love of neighbor. Neighbors that see we care for their physical safety may then be more receptive to understand the second greatest commandment and pass it forward themselves. That understanding may then cultivate a readiness to understand the greatest commandment: to love the God from whom all good things come.
Epilogue
Although some Rhine River castle sites date as far back as the 12th century, around the 14th century castles no longer provided safety to the monarch and his subjects. A disruptive technology was invented in China and became a widespread tool of war in Europe in the 14th century: the cannon. Rounded towers replaced square structures because they withstood glancing cannonball blows somewhat better. Eventually castles gave way to star forts, which used sloped, angled walls and shorter, stouter earth and breastworks and stone battlements.
The old castle ruins remained for hundreds of years until refurbished in the 19th century. However, the refurbishments tended to fantasize how a castle should appear, with lofty towers reaching to the sky, large windows, and broad archways that satisfied the whimsy of the romantic period. Thus the castles we see along the Rhine today are beautiful, but do not accurately depict the previous historical structures. The real castles of previous ages were much less romantic but much more defensible. In architecture, a “folly” is a building constructed primarily for decoration, but it is built to look like it has another purpose. (Headley and Meulenkamp, Follies: A Guide to Rogue Architecture. 1986). What an apt name for these faux castles. But also an apt description for our pursuit of safety through our own devices and own power. It is true folly to place our trust in anything besides our all-powerful and loving God.
One final thought. Safety is a good thing that we seek for ourselves. God does not ask us to stop behaving safely or seeking safe environments. Rather, we must put God above our personal safety needs, and put our neighbor’s safety needs above (or at least equal to) our own. Likewise with other good things: health, justice, prosperity, peace, and so forth. We may rightly seek them, if ordered correctly. We must seek them for our neighbor as much as ourselves, and we must pursue God more than any of these, for God is our greatest good.

![[Portcullis image Kevin King from Pensacola, FL, US of A, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons]](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwaLCbEjProyZL-lhBRnerH6eCdfjKaZYvBpbCzvi62vMuCW1F2KpIpeQ61Ejf70datT7uKof41EBgQRoWZDDUxEN9sAdry1Q95W1EtntVOHOakAFh0r23CU_iysQ1Ko__EF6fyYAkio3RxK1kAIT8ghXFas-4wqqbYbb6pvJxyKrg8RROdA94n6D1eGVp/w320-h209/Cahir_Castle_Portcullis_by_Kevin_King.jpg)













