There is no scientific foundation for it. Jung dreamt it up with an extremely literary approach. Then the swindlers Briggs and Myers popularised it with their 20th century astrology.
The introversion-extraversion personality axis is the only part of the MBTI that modern psychometrics accepts basically without reservation. It lives on as the introversion-extraversion factor of the Big 5 Personality Model.
I find it interesting that the rest of the MBTI is so thoroughly rejected -- in particular, I read in work that accepts the MBTI (uh-oh, red flag!) that males tend to split 75% T / 25% F and females do the reverse, 75% F / 25% T.
It seems to me that this very large difference in responses should be sufficient to show that the T / F axis is capturing something. If the T / F distinction were meaningless, it wouldn't be able to predict anything, but it clearly can predict the respondent's sex.
https://en.wikipedia.org/wiki/Big_Five_personality_traits
I find it interesting that the rest of the MBTI is so thoroughly rejected -- in particular, I read in work that accepts the MBTI (uh-oh, red flag!) that males tend to split 75% T / 25% F and females do the reverse, 75% F / 25% T.
It seems to me that this very large difference in responses should be sufficient to show that the T / F axis is capturing something. If the T / F distinction were meaningless, it wouldn't be able to predict anything, but it clearly can predict the respondent's sex.