Skolem was right

From the paper by Paul Cohen…”Skolem and pessimism about proof in mathematics“

“Skolem, in his papers, was so struck by the existence of non-isomorphic models of
all but the most trivial axiom systems that he was led to doubt the relevance of
any mathematical axiom system to the philosophical questions concerning
foundations of mathematics. For example, he pointed out the existence of
countable models of set theory. He seems to have been the first clearly to
emphasize models rather than methods of proof.”

Seriously, read the whole paper!