I’m not arguing against type theories, not arguing against the usefulness of various forms of type inference, not arguing against reasonable requests, not arguing against the desire to reason about code, not arguing against tools to ensure correctness and all that good stuff.

I am arguing against the belief that types belong in the compiler and not in the running system, and I am arguing that the specific idea of a “parameterized type” is moot in Common Lisp, both because we have typed objects and because we have a type hierarchy for all types with specialization on disjoint types.

I am arguing that parameterized types are necessary when you accept disjoint types and believe in the compiler as your only savior.