The woman, Isabel, was a stranger to her son

He saw little essential difference between thirty-eight and eighty-eight, and his mother was to him not a woman but wholly a mother. He had no perception of her other than as an adjunct to himself, his mother; nor could he imagine her thinking or doing anything —falling in love, walking with a friend, or reading a book —as a woman, and not as his mother. The woman, Isabel, was a stranger to her son; as completely a stranger as if he had never in his life seen her or heard her voice.

in The Magnificent Ambersons por Booth Tarkington