Samuel admits that he's somewhat afraid of Natasha now because of her unexplainable interest in chemistry and math. He's afraid that her world is now bigger than him. One night, after Natasha and Peter were asleep, he'd flipped through her math book. The strange symbols filled him with dread. After that, he felt as though someone had snuck in and taken his sweet daughter away when he wasn't looking. Sometimes, however, he'll catch a look from her that reminds him of when she was younger. It's a look that wants him to do more. He resents her for it, since he feels like he's already given up all his dreams for her.
Samuel's fear of math and chemistry suggests that like Natasha, he believes that hard subjects like those are in direct opposition to passion and the arts. His language suggests that he's given up on trying to make his situation any better, and to cope, he's isolating himself.