she began to finger her toes, and so I had her shoes and socks removed… it looked as if she was discovering and proving over and over again, to her great satisfaction, that whereas spatulas can be put to the mouth, thrown away and lost, toes cannot be pulled off.
Winnicott identifies the infant’s exploration of her own toes as a pivotal developmental discovery: toes, unlike external objects, are inalienable parts of the self, establishing a foundational distinction between self and world.
, Playing and Reality, 1971thesis