I tried digging through both the article, SICP and your comment, and here are my thoughts: I think both statements are correct in their context. The perma-curi

I tried digging through both the article, SICP and your comment, and here are my thoughts: I think both statements are correct in their context. The perma-curious.eu article is right about the eval-apply cycle as presented in SICP. The SICP metacircular evaluator presents eval and apply as two mutually recursive procedures that form the core of a Lisp interpreter. In this implementation, apply does evaluate arguments indirectly through eval. The mutual recursion between eval and apply is indeed fundamental to Lisp, and it's clearly explained in the "wizard book". The call-by-value evaluation strategy is also correctly described - arguments are evaluated before being passed to functions. This eval-apply cycle forms the essence of Lisp's execution model. But your comment is also valid, your correction is more precise: - apply is indeed a function that takes already-evaluated arguments - eval does the evaluation of arguments before calling apply - apply simply binds and executes the function with its arguments - The relationship isn't truly dual - apply depends on eval, but not vice versa I think the confusion came from conflating the built-in apply function with the apply procedure used in implementing an interpreter.