You can logically reason about any language. It's just a matter of ease and the amount of code you have to see to be able to get a full picture. I mean, ultimat

You can logically reason about any language. It's just a matter of ease and the amount of code you have to see to be able to get a full picture. I mean, ultimately I could follow the logic of the program through the compiler/interpreter all the way down to the machine level and reason about the specific instructions executed on the processor. And when you have hard performance requirements you sometimes have to get that low. So by that definition of reasonableness all languages are reasonable. But of course he is making a pun and implying the more typical meaning of (un)reasonable, using it as a slight to languages that don't meet his criteria. I don't actually disagree with most of his guidelines, but I really don't like his use of that term. There are many situations where his preferences are actually unreasonable and the the opposite of what he has concluded is appropriate, mutable state being an easy example. It should not be a "I'm right and you're unreasonable" type of discussion.