For years I've been meaning to post an opinion on "Psychological Types" in this thread. But I needed to put together an essay to explain my opinion, and I never found time for that. However, this morning I poked through the abstract that
@Kephalos linked above, it reminded me of the book in detail, and finally I took a few minutes and put together some thoughts on the book:
Anyway, there is a lot of historical background to "Psychological Types" that Jung didn't really provide. So readers often have a difficult time even figuring out what the book is about. But in many ways the book encapsulates why Freud and Jung split up, and it's Jung's way of proclaiming his independence from Freud.
Here's some of the background:
Jung & Freud collaborated during 1907-1913, that is, for six years. They had very different training and background, and there were frictions between them right from the start. But Freud was the big guru, and Jung swallowed his pride for some time.
One area of contention: Freud was an extravert, and Freud was of the opinion that extraversion was healthy whereas introversion was unhealthy or pathological. Jung went along with this theory for a while (even though he himself was an introvert). In 1912 Jung himself described introversion as "an archaic and regressive phenomenon, i.e., as a relapse into a primitive mode of functioning."
Meanwhile a psychologist named Alfred Adler had split from Freud's circle in 1911 and was proposing competing psychological theories that seemed to suggest that introversion could be healthy. (Adler himself was apparently an introvert.)
By 1913 Jung and Freud were drifting apart. Also, Jung was increasingly of the opinion that introversion and extraversion were both equally healthy. In a 1913 lecture, Jung gave an early presentation on "Psychological Types" (provided in the book as an Appendix at the end under the name "A Contribution to the Study of Psychological Types"). Jung said at the end of the presentation that Freudian psychology is extraverted and emotional while Adlerian psychology is introverted and thinking. A footnote states that this presentation was the last time Freud and Jung ever met. (p. 499)
From 1913 to 1921 Jung went through what he called a "fallow period," but he was clearly working on "Psychological Types." In a 1917 essay "On the Psychology of the Unconscious," he talks at length about the Freud-vs-Adler dichotomy. For example:
"We are certainly not entitled to discard one in favour of the other, however convenient this expedient might be. For, if we examine the two theories without prejudice, we cannot deny that both contain significant truths, and, contradictory as these are, they should not be regarded as mutually exclusive. The Freudian theory is attractively simple, so much so that it almost pains one if anybody drives in the wedge of a contrary assertion. But the same is true of Adler's theory. It too is of illuminating simplicity and explains just as much as the Freudian theory. No wonder, then, that the adherents of both schools obstinately cling to their one-sided truths. For humanly understandable reasons they are unwilling to give up a beautiful, rounded theory in exchange for a paradox, or, worse still, lose themselves in the confusion of contradictory points of view.
"Now, since both theories are in a large measure correct - that is to say, since they both appear to explain their material - it follows that a neurosis must have two opposite aspects, one of which is grasped by the Freudian, the other by the Adlerian theory. But how comes it that each investigator sees only one side, and why does each maintain that he has the only valid view? It must come from the fact that, owing to his psychological peculiarity, each investigator most readily sees that factor in the neurosis which corresponds to his peculiarity. It cannot be assumed that the cases of neurosis seen by Adler are totally different from those seen by Freud. Both are obviously working with the same material; but because of personal peculiarities they each see things from a different angle, and thus they evolve fundamentally different views and theories."
And so on. In fact, Jung kind of made it his mission to reconcile the Freudian and Adlerian schools and explain how both could be right at the same time.
And that is basically the background for "Psychological Types," which was published four years later in 1921. "Psychological Types" is a grand survey of history showing how all the big academic disputes and debates throughout much of human history basically boiled down to an introverted point of view competing with an extraverted point of view. And both views captured a
part of the truth but rarely
all of the truth.
In "Psychological Types" itself, Jung didn't bother to go into a long explanation of the Freud-vs-Adler dichotomy and the background of the book. (Freud and Adler are only mentioned in passing around pages 60-62.) But the book wasn't written for laymen. The intended audience was professional psychologists, and they would have been well aware of the Freud-Adler split and would have recognized "Psychological Types" as Jung's attempt to explain that split. They already knew the background.
Also, "Psychological Types" was written for intellectuals with education in the classics. Readers of the book in 1921 would have understood the historical references like Tertullian and Origen, the Gnostics, the early Church fathers, Schiller, etc.
So it's perfectly understandable that modern readers in 2021 are going to have difficulty reading a technical psychological manual written for intellectuals in 1921. Especially when Jung didn't even bother to explain why he wrote the book in the first place (that is, he didn't explain the Freud-vs-Adler dichotomy as the starting point for the book).
But Jung is clear enough about the book's message in the Introduction (pages 3-7). He comes right out and says it: It's about Extraversion vs Introversion. And basically that's it: Just a survey of Extraversion vs Introversion throughout the ages. Meantime, the cognitive functions appear as kind of a footnote, to explain why introversion or extraversion in one person can appear very different from introversion or extraversion in another person: It's because there are four different types of introversion (Ni, Si, Ti, Fi) and also four different types of extraversion (Ne, Se, Te, and Fe). And furthermore, we all can switch from introverted to extraverted or vice versa by virtue of switching from our Dominant function to our Auxiliary function.
But that's basically the entire book: Extraversion vs Introversion. It's a very boring read for most laymen today. But it was important at the time. Just by virtue of the sheer scope of the book, it pretty much laid the issue of Extraversion vs Introversion to rest once and for all. And it also marked Jung's full independence from Freud and his emergence as an original thinker in his own right. Jung was trying to be respectful of both Freud and Adler and the work they had done, but Jung was kind of setting himself up as judge over the two of them and proclaiming that henceforth he would be calling his own shots and represent a third major voice in psychology.
If you want to read more on the Freud-vs-Adler conflict and Jung's role in resolving it, see the Wikipedia article on "Psychological Types," and go down to the section entitled "Historical Context." Link:
https://en.wikipedia.org/wiki/Psychological_Types#Historical_context
Anyway, I'm giving the book two stars. "Psychological Types" was an important book at the time it was published, but it's practically unreadable today. To anyone reading it today, I would say: Read the introduction (pages 3-7) and then chapters 6-9 (which are less historical and more about modern concepts of psychology). And then of course chapter 10, which goes into the cognitive functions. But unless you have a classical education, avoid chapters 1-5 like the plague: That will save you 270 pages of material about obscure, unfathomable historical academic debates.