The thing about dynamic languages is that they have a type system too, but it's called "inheritance." When literally everything in your language is an object th

The thing about dynamic languages is that they have a type system too, but it's called "inheritance." When literally everything in your language is an object that ultimately inherits from Object, as it is in Ruby or Python or Javascript, it doesn't matter what "type" each of your objects is, it just matters that your objects define the fields you want to access and respond to the methods you want to call on them (And Ruby even lets you fail up the object tree with method_missing). Fixating on types is focusing on the wrong thing. You need to understand the object inheritance tree, not the types. Whether or not that makes your code unmaintainable is up to you, it helps if you keep your classes small and give each of them a well-defined and documented purpose. But that's just good coding practice in general. Also, static code analysis is nice, but it can't determine everything about your code; Turing proved that in 1936. Meanwhile, by skipping the the compiler and linker, you can deploy enhancements and bug fixes to a running program without shutting it down and restarting it. For a rather long but enjoyable read on why this is important for long-lasting software, see: http://steve-yegge.blogspot.com/2007/01/pinocchio-problem.html http://steve-yegge.blogspot.com/2007/01/pinocchio-problem.ht...