C. J. Jung in his marvelous book Psychological Types identifies four conscious functions. They are thinking, intuition, sensation, and feeling. Almost everyone will favor one of these conscious functions and use another of the functions to complement the principal one. Holden Caulfield seems to rely heavily on intuition and feeliing. This is probably the most striking aspect of "The Catcher in the Rye." Holden makes snap thumbnail assessments of people based on how he feels about them--and his judgments are often right. If it were not for this feature of the novel, it would not be nearly as interesting as it is or as popular as it has been for over sixty years. His feeling tells him whether he likes or dislikes, trusts or distrusts a person, and then his intuition gives him more details about that person's character and even about people in the entire category to which the person belongs. A good example is in his run-in with Maurice the bellhop, who is a total stranger. After Maurice robs him of five dollars, Holden actually prophesies the petty thug's future life:
"You're a stupid chiseling moron, and in about two years you'll be one of those scraggy guys that come up to you on the street and ask for a dime for coffee. You'll have snot all over your dirty filthy overcoat, and you'll be--"
Holden's primary conscious function cannot be called "thinking" because he is too immature. But he may develop into a person who relies more on thinking and intuition than on feeling and intuition.
Your question about "knowing and feeling" is perceptive. "Knowing" is the same as intuition (or intuiting), and it is a wonderful ability to have. It comes, as Jung tells us, from the unconscious, which contains the wisdom and condensed experience accumulated by the human race during the past two million years.