So, granted that Scott and the author of W are identical (s = aw), from (23, 36) it follows that Scott and the author of W are contingently identical.
(23) for allx(¬necessarily(x = x) if-then ¬for somey((x = y) & necessarily(x = y)))

(36) ¬necessarily(aw = aw)

(37) (s = aw) & ¬necessarily(s = aw)