by nature
El hombre es un animal político por naturaleza.
Man is a political animal by nature.
He is like that by nature.
Todos los hombres se odian por naturaleza.
All men hate each other by nature.
Por naturaleza sigo siendo un chico, no una chica.
By nature I am still a boy, not a girl.
— Adiós a mi concubina (1993)
He was passive by nature.
Helen es optimista por naturaleza.
Helen is optimistic by nature.
El hombre es un animal social por naturaleza.
Man is a social animal by nature.
Ella tiene un buen corazón por naturaleza.
She has a good heart by nature.