The article's most interesting point is that the vast majority of possible program (or object) states tend to be invalid. For example, `Person(isWalking=true, isAlive=false)` is nonsense, because there's an unexpressed constraint that `isWalking==true ==> isAlive==true`.

Though the author veers in another direction, I think his core point is related to this discussion:

Applying “make invalid states unrepresentable” https://news.ycombinator.com/item?id=24685772