Scouts Honor

Yesterday we looked at how theology can inform software development, today we consider physics. The second law of thermodynamics states:

The total entropy of an isolated system can only increase over time.

This statement has a specific technical meaning which is worth investigating on its own merits, but the general principle is that systems tend towards decay. Software systems are no exception to this rule, variously described as software entropy or code rot. Anyone who has worked with software for any length of time knows firsthand how clean code quickly devolves into spaghetti.

How can one combat this seeming inevitability? The key lies in the second law and the little phrase “of an isolated system”. Essentially entropy can be held steady or even reversed in a system if it is properly influenced from outside that system. In the world of software this means that every time a change is made, one should not just do the minimum required to implement the change, because any edit likely increases entropy. Instead the developer must go further to leave the code better than she found it (what Uncle Bob described as the Boy Scout Rule). The best developers work to make this second nature.

Yes this takes more time in the short run. But it’s essential to the long-term health of a software system.