Spec-ulation

I've been thinking about versioning (for work) lately and I'm reminded of Rich Hickey's take on it from his Spec-ulation talk. The gist of it is that it’s more useful to think in terms of breakages and accretions as opposed to the more vague notion of “versions”. He (perhaps controversially) suggests that breaking changes should just be considered new things, the concept of having a new “version” of something that is not compatible with the old one is incoherent if you think about it.