Help:"Ser" and "este"

Portuguese and Spanish have two different verbs that are usually translated to English as “to be”: ser relates to essence, contrasting with estar, which relates to state.

Spanish

Contrast the following Spanish phrases:

• El hombre está felíz.—“The man is [currently] happy.”
• El hombre es felíz.—“The man is [always] happy.”
• ¿Estás loco?—“Are you crazy [currently out of your mind]?”
• ¿Eres loco?—“Are you crazy [permanently insane]?”
• El hombre está en España. — “The man is [currently] in Spain.”
• El hombre es de España. — “The man is [originally] from Spain.”

Portuguese

The same phenomenon occurs in Portuguese.

• ser is to be in the sense of a property of the subject, usually something intrinsic to it, somewhat permanent or long-term. For example, ser would be used to say "he is Portuguese", because being Portuguese is an attribute of that person, not a transitory state. The same would occur in less obvious and not always unambiguous cases, such as saying "I am married" (in the sense of "I'm a married person").
• estar is to be in the sense of a somewhat transient state of the subject, such as in "I am tired".

Some examples:

• I am blind: you would use "ser" to state you are a blind person, but would otherwise use "estar" if you are temporarily blind (such as after an explosion, or after having your eyes pepper-sprayed).
• I am white: "ser" for the racial context, but "estar" if you suddenly realize you are covered in white paint.
• I am Bill: only "ser" is admissible here.
• I am standing: only "estar" is admissible here, as a transient state (standing is not a characteristic of your being).