IQ is a single number for a very good reason. If you take all the questions psychology researchers have come up with to try to measure intelligence, take the pa

IQ is a single number for a very good reason. If you take all the questions psychology researchers have come up with to try to measure intelligence, take the pass/fail statistics of test-takers on them, and run a principle component analysis on it, you wind up with a single dimension. There's no forcing the data to be single-dimensional regardless of the underlying truth about intelligence. People genuinely made an attempt to measure intelligence, and the measures people came up with happened to measure something best described as a single number. Psychology researchers have tried to do the same with personality, and the principle component analysis spit out five dimensions rather than one. That's why the "Big 5" personality traits (Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism) are a thing.