The trouble is, the more you look into the specifics of the MBTI, the more questionable the way it’s widespread use appears to be. There are numerous comprehensive critiques about it online, but the most obvious flaw is that the MBTI seems to rely exclusively on binary choices.
For example, in the category of extrovert v introvert, you’re either one or the other; there is no middle ground. People don’t work this way, no normal person is either 100% extrovert or 100% introvert, just as people’s political views aren’t purely “communist” or “fascist”. Many who use the MBTI claim otherwise, despite the fact that Jung himself disagreed with this and statistical analysis reveals even data produced by the test shows a normal distribution rather than bimodal, refuting the either/or claims of the MBTI. But still this overly-simplified interpretation of human personality endures, even in the Guardian Science section!
Generally, although not completely unscientific, the MBTI gives a ridiculously limited and simplified view of human personality, which is avery complex and tricky concept to pin down and study. The scientific study of personality is indeed a valid discipline, and there are many personality tests that seemingly hold up to scientific scrutiny (thus far). It just appears that MBTI isn’t one of them.
But so what? People often benefit from things with a limited scientific basis, for many reasons. Scientific validity is necessary if you’re trying to diagnose a disorder of some sort, but in the everyday workplace for team building and the like? This is what MBTI is used for most, so why go on some major nerd-rant about how unscientific it is when it doesn’t really matter?
Yes, the MBTI is harmless and potentially useful if you’re aware of its limitations. That’s the problem, though; the MBTI is predominately used in the workplace by HR departments, development/training teams and the like, who can often be clearly unaware of its limitations.