Actually, "Jung himself" said (in the Foreword to
Psychological Types):
[Psychological Types] is the fruit of nearly twenty years' work in the domain of practical psychology. It grew gradually in my thoughts, taking shape from the countless impressions and experiences of a psychiatrist in the treatment of nervous illnesses, from intercourse with men and women of all social levels, from my personal dealings with friend and foe alike, and, finally, from a critique of my own psychological peculiarity.
And mystical streak notwithstanding, and although he hardly believed that science had all the answers, Jung believed in applying scientific methods and standards to the field of psychology to the extent possible.
In one of the articles included in the
Collected Works edition of
Psychological Types, Jung brought up astrology — along with several other "age-old" typologies — solely to dismiss it as unacceptable as a tool for psychological analysis. "As for the astrological type theory," Jung wrote, "to the astonishment of the enlightened it still remains intact today, and is even enjoying a new vogue." By contrast, Jung explained, "our scientific conscience does not permit us to revert to these old, intuitive ways of thinking. We must find our own answer to this problem, an answer which satisfies the needs of science."
Years after
Psychological Types was published, Isabel Myers devoted a substantial chunk of her life to putting its typological concepts to the test in a way that Jung never had, and in accordance with the psychometric standards applicable to the
science of personality.
After a
large meta-review of the existing data, supplemented by a large supplemental study, in 2003, Robert Harvey and his co-authors summed up the MBTI's relative standing in the personality type field this way:
In addition to research focused on the application of the MBTI to solve applied assessment problems, a number of studies of its psychometric properties have also been performed (e.g., Harvey & Murry, 1994; Harvey, Murry, & Markham, 1994; Harvey, Murry, & Stamoulis, 1995; Johnson & Saunders, 1990; Sipps, Alexander, & Freidt, 1985; Thompson & Borrello, 1986, 1989; Tischler, 1994; Tzeng, Outcalt, Boyer, Ware, & Landis, 1984). Somewhat surprisingly, given the intensity of criticisms offered by its detractors (e.g., Pittenger, 1993), a review and meta-analysis of a large number of reliability and validity studies (Harvey, 1996) concluded that in terms of these traditional psychometric criteria, the MBTI performed quite well, being clearly on a par with results obtained using more well-accepted personality tests.
...and they went on to describe the results of their own 11,000-subject study, which they specifically noted were inconsistent with the notion that the MBTI was somehow of "lower psychometric quality" than Big Five (
aka FFM) tests. They said:
In sum, although the MBTI is very widely used in organizations, with literally millions of administrations being given annually (e.g., Moore, 1987; Suplee, 1991), the criticisms of it that have been offered by its vocal detractors (e.g., Pittenger, 1993) have led some psychologists to view it as being of lower psychometric quality in comparison to more recent tests based on the FFM (e.g., McCrae & Costa, 1987). In contrast, we find the findings reported above — especially when viewed in the context of previous confirmatory factor analytic research on the MBTI, and meta-analytic reviews of MBTI reliability and validity studies (Harvey, 1996) — to provide a very firm empirical foundation that can be used to justify the use of the MBTI as a personality assessment device in applied organizational settings.
McCrae and Costa are the leading Big Five psychologists, and authors of the NEO-PI-R, and after reviewing the MBTI's history and status (including performing their own psychometric analysis) back in 1990 — using an earlier version of the MBTI (Form G) than the one being used today —
they concluded that the MBTI and the Big Five might each have things to teach the other, approvingly pointed to the MBTI's "extensive empirical literature," and suggested that their fellow Big Five typologists could benefit by reviewing MBTI studies for additional insights into those dimensions of personality, as well as "valuable replications" of Big Five studies.
And for the benefit of anyone who's new to TC, let me note that I've corrected Mole on this issue multiple times (e.g.,
here), but he keeps coming back with the same nonsense.
Anyone who's interested can read quite a lot about the scientific respectability of the MBTI, and how it compares to the Big Five — and about several other issues often raised by people claiming to "debunk" the MBTI — in
this TC Wiki article.
If he ever wakes up from his "sleep of reason," maybe Mole will give it a read.