The Rationalist's Fence

As software engineers, we are constantly creating. But there are always times that, rather than build out new features, we must support older features to cover up for edge cases that weren’t foreseen during the original development process. More often than not, this work is benign, but sometimes, there’s a certain piece of code that constantly seems to require maintenance.

We’ve often wanted to just remove and re-write this functionality, but, depending on your team’s leadership, you may not always be able to make the change you want because it exists for a reason, and we cannot remove something if there’s a good reason for it to exist.

Chesterton’s Fence is an axiom devised from a quote by G.K. Chesterson in his 1929 book “The Thing”.

There exists in such a case a certain institution or law; let us say, for the sake of simplicity, a fence or gate erected across a road. The more modern type of reformer goes gaily up to it and says, “I don’t see the use of this; let us clear it away.” To which the more intelligent type of reformer will do well to answer: “If you don’t see the use of it, I certainly won’t let you clear it away. Go away and think. Then, when you can come back and tell me that you do see the use of it, I may allow you to destroy it.”

― The Thing by G.K. Chesterton, 1929

In modern times, this belief is touted as the cornerstone of modern conservative thought. Roughly translated, it embodies the desire to conserve what has been given to us - especially if we’re unsure of why it was created to begin with. I generally have no problem this line of thinking as the history of the thing is often more important than the thing itself, and if you destroy something, you largely destroy its history. So it behooves you to preserve that history before taking such action. But, oftentimes, the reason for a thing’s existence is used to deter would-be reformers from destroying it.

Now, we come to the concept of rationalism. Rationalism is the idea that human beings can devise morality through reason. The rationalist sees a world full of reason. Every thing in front of them has a reason to exist, and that’s why it exists.

This lofty ideology sounds great in theory, and it’s often touted as the way to end the global strife caused by religion. However, if we’re to scientifically derive a proper “rational” truth, we must trust our instrument. Our data must be reliable and precise. The problem arises in the fact that every human being perceives the world differently and holds in their mind a drastically different model of reality. Obviously, this inconsistency must be accounted for. We must appoint a few well-thinking individuals as the most prominent intellectuals who are responsible for deriving the truth. Jonathan Haidt describes this well:

As an institutionalist, I’d say the worship of reason is itself an illustration of one of the most long-lived delusions in Western history: the rationalist delusion. It’s the idea that reasoning is our most noble attribute, one that makes us like the gods (for Plato) or that brings us beyond the “delusion” of believing in gods (for the New Atheists). The rationalist delusion is not just a claim about human nature. It’s also a claim that the rational caste (philosophers or scientists) should have more power, and it usually comes along with a utopian program for raising more rational children.

- The Righteous Mind by Jonathan Haidt, 2012, p.103

Haidt, who doesn’t come across as a very religious man, in fact he has his criticisms of the religious right in the book I quoted above, assigns religious analogies to what purports to be an areligious endeavor. I cannot overstate how important this book is in understanding how different people perceive morality. But I digress. Using this model, I can proceed.

To the novice rationalist (or just the unthinking acolyte), who hasn’t memorized the reason for most things' existence, they just assume everything around them was carefully planned and placed there to their advantage. The thing begets a reason. This kind of thinking creates an indestructable fence as the novice lacks the mental clarity to perceive the reason for a thing’s existence, thus they cannot be allowed to destroy it.

The difference between Chesterton’s Fence and the Rationalist’s Fence is that Chesterton allows for an individual to wholly consume the fence and its history before destroying it. The Rationalist simply absorbs reason from their priest and takes whatever action is afforded them. We cannot all be rational as some people are more rational than others. In one model, the fence can be destroyed. In the other, we must arbitrarily accept the existence of things until we’re allowed to rise up to be among our intellectual peers.

In software, we exist in multiple realities at any given time. We see into these imperfect futures and select the one that better fits our needs. Then, we study the present in which we find ourselves to see if it meets our prediction. We must then either accept the concrete present or imagine ourselves in another imperfect future. If we are to better our small universe, we cannot limit ourselves to only a few possible futures. We must understand the history of the pieces that make it up so that we can better predict where we can take it. And if another individual comes along and wants to destroy our creations, we ask them to first understand why the thing exists. And then we allow them to destroy it.