When viewing NTJs, Keirsey says they use deduction over induction. Once again, Keirsey completely missed the boat. INTJs use intuition almost exclusively, using deduction only if needed. ENTJs use deduction, however.
It's amazing. His correlation between the functional types and the four temperaments is absolute genius. What drove him to incorrectly redefine the letters, is mind boggling. As right as he is about the correlation, he is even more wrong on the letter definitions.