diff --git a/pkgs/racket-doc/scribblings/reference/eval-model.scrbl b/pkgs/racket-doc/scribblings/reference/eval-model.scrbl
index 2e04f7a075..d496022aff 100644
--- a/pkgs/racket-doc/scribblings/reference/eval-model.scrbl
+++ b/pkgs/racket-doc/scribblings/reference/eval-model.scrbl
@@ -386,9 +386,9 @@ an @tech{object}, so evaluating @racket[(f 7)] starts with a
 Unlike in algebra, however, the @tech{value} associated with a procedure
 argument variable can be changed in the body of a procedure by using
 @racket[set!], as in the example @racket[(lambda (x) (begin (set! x 3)
-x))]. Since the @tech{value} associated with argument variable @racket[x] can be
-changed, the value cannot be substituted for @racket[x] when
-the procedure is first applied.
+x))]. Since the @tech{value} associated with argument variable @racket[x] should be
+able to change, we cannot just substitute the value in for @racket[x] when
+we first apply the procedure.
 
 @margin-note{We do not use the term ``parameter variable'' to refer to
 the argument variable names declared with a function. This choice avoids