In fairness to @failed_buddhist, you don't need to see them as being at the same level.
That said, I hardly think MBTI is valid as such - and I say that as someone who used to be able to ascertain someone's MBTI type with very high probability (~80% agreement with test results.)
Go ahead, find reliable behavioural correlates of MBTI types. It's extremely difficult, but if you can find something replicable I'll grant you that.
Most personality typologies suffer from this lack of clear relationship with behaviour, yet they make assertions about it...