On thePHP.cc blog Stefan Priebsch offers up an interesting opinion about code, developers and understanding - developers shouldn't code.
The ultimate problem with program code seems to be that no human really understands it. Sure, we can look at a short piece of code and be relatively clear on what it does, but can we still do the same thing with programs that span tens or even hundreds of thousands of lines?[...] Well, sometimes I get a strong feeling that there is a shortage of good programmers, because I often find myself looking at legacy code, being unable to tell what it does, at least with reasonable certainty. [...] Personally, I already consider code to be problematic when there is a reasonable amount of doubt as to what it does (and why it exists). To me, uncertainty and discussions are a sure sign of bad code. Call me picky, but years of experience have taught me that this level of strictness makes sense.
He suggests that the fact a developer cannot recognize what current code is doing doesn't make you a poor developer, but the opposite. He talks some about the meaning of the word "code" and how it is written for a machine to understand, not a human. He ends the post talking about testing your code to provide an "executable specification" and, despite having this, a human-readable spec is still a requirement (like it or not).