Imagine a 4 billion year old codebase, written by dice throws and unit testing.
The immune system is a "complicated" thing to work with.
The immune system is a "complicated" thing to work with.
That's a great analogy, except it doesn't go quite far enough. The code for the toolchain that compiles the codebase (not to mention the unit testing framework) is just as old, and written the same way.
My favorite dad quip was 'Biology itself is proof against an intelligent designer.'
Evolution isn't going to nicely separate functionality into clean, single-purpose biochemical pathways.
It's going to overload something that it already has to support a new feature, leading to a rat's nest of intertwined effects.
The hard part in drug development isn't affecting your target: that's pretty easy to guarantee with modern tools. It's finding out that that target also governs 10 other, completely unrelated bodily functions.
Some companies in the valley just call that Wednesday.=)
Did you mean integration testing?
Evolution unit tests, then integrates in prod.