Dynamic languages are static languages
existentialtype.wordpress.com
existentialtype.wordpress.com
Yes, obviously you can view a dynamic language as having only a "top" type. That's largely the point.
As for the post, I'm assuming it was written as some kind of tongue-in-cheek reverse troll, as I'd really like to believe Robert Harper doesn't drip condescension like that without being fully aware of it.
Every time this is brought up I always imagine writing a complete library to support a super-type for some static language that has tagged unions and operator overloading such that the user will rarely if ever need to inspect the type tag. And the more I think about this the more I realize you'd get gradual typing on primitives for free.