In practice, there is such a thing as "more or less sound" and there are no perfect circles. None of these things bother me. I responded to you because it seem

In practice, there is such a thing as "more or less sound" and there are no perfect circles. None of these things bother me. I responded to you because it seemed (no snark intended) that "more or less sound" things existing bothers you. The person who mentioned "more or less sound things" was referring to those things that exist in practice. The local discussion was (I thought) about type systems that exist in practice in the sense that a real practical C compiler has one. I think OP was justified in talking about this here, even if the article does not, because the theory exists at least in part to inform practice.