Semantics. Spec is very close to dependent types. "Entirely different purpose" is kinda vague. If the end result is the correctness of the program, the purpose

Semantics. Spec is very close to dependent types. "Entirely different purpose" is kinda vague. If the end result is the correctness of the program, the purpose is the same. If someone can perform Vivaldi's Four Seasons on Ukelele, it's cool. It doesn't make Ukelele less of an instrument.