Synthesized answer
Keynes characterizes Wilson's temperament as "theological not intellectual" because Wilson's thought and manner of expression, with their associated strengths and weaknesses, were essentially like those of a Nonconformist minister, perhaps a Presbyterian [1]. This is further elaborated by stating that he could preach a sermon on his ideas or address a prayer for their fulfillment, but could not frame their concrete application [5].
This theological temperament meant that when compromises became necessary, Wilson remained a man of principle, viewing the Fourteen Points as an absolutely binding contract. He would do nothing dishonorable, unjust, right, or contrary to his great profession of faith. This led to the Fourteen Points becoming a document for gloss and interpretation, a method he shared with his ancestors who used similar intellectual apparatus to reconcile their actions with religious texts [2]. This "theological or Presbyterian temperament became dangerous" when he had to make concessions, as his defects in temperament and equipment were apparent when he stepped down from a high line of principle [4].
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
ident was not the philosopher-king, what was he? After all he was a man who had spent much of his life at a University. He was by no means a business man or an ordinary party politician, but a man of force, personality, and importance. What, then, was his temperament? The clue once found was illuminating. The President was like a Nonconformist minister, perhaps a Presbyterian. His thought and his temperament wore essentially theological not intellectual, with all the strength and the weakness of that manner of thought, feeling, and expression. It is a type of which there are not now in…
ancial power of the United States to secure as much as he could of the substance, even at some sacrifice of the letter. But the President was not capable of so clear an understanding with himself as this implied. He was too conscientious. Although compromises were now necessary, he remained a man of principle and the Fourteen Points a contract absolutely binding upon him. He would do nothing that was not honorable; he would do nothing that was not just and right; he would do nothing that was contrary to his great profession of faith. Thus, without any abatement of the verbal…
d wiser when he was seated; and his hands, though capable and fairly strong, were wanting in sensitiveness and finesse. The first glance at the President suggested not only that, whatever else he might be, his temperament was not primarily that of the student or the scholar, but that he had not much even of that culture of the world which marks M. Clemenceau and Mr. Balfour as exquisitely cultivated gentlemen of their class and generation. But more serious than this, he was not only insensitive to his surroundings in the external sense, he was not sensitive to his environment at all.…
resident must be trusted to do his best. And in this drought the flower of the President's faith withered and dried up. Thus it came to pass that the President countermanded the _George Washington_, which, in a moment of well-founded rage, he had ordered to be in readiness to carry him from the treacherous halls of Paris back to the seat of his authority, where he could have felt himself again. But as soon, alas, as he had taken the road of compromise, the defects, already indicated, of his temperament and of his equipment, were fatally apparent. He could take the high line; he could…
o criticize details,--the details, they felt, were quite rightly not filled in at present, but would be in due course. It was commonly believed at the commencement of the Paris Conference that the President had thought out, with the aid of a large body of advisers, a comprehensive scheme not only for the League of Nations, but for the embodiment of the Fourteen Points in an actual Treaty of Peace. But in fact the President had thought out nothing; when it came to practice his ideas were nebulous and incomplete. He had no plan, no scheme, no constructive ideas whatever for clothing…