If “intelligence” is just the degree/quality of someone’s brain function then your intelligence does drop when your brain function is impaired, and you would expect that to be picked up in an intelligence test.
Culturally we may want to imagine intelligence as something constant and innate to somebody’s soul, but in reality it’s innate to a fragile and fickle organ inside your skull.
If “intelligence” is just the degree/quality of someone’s brain function then your intelligence does drop when your brain function is impaired, and you would expect that to be picked up in an intelligence test.
Culturally we may want to imagine intelligence as something constant and innate to somebody’s soul, but in reality it’s innate to a fragile and fickle organ inside your skull.