The Gate of Angels is Fitzgerald's stab at a university comedy along the lines of Lucky Jim. Those novels feel British in a peculiar way, because college in the United States is so vastly different, with its own kind of pretensions and strange ritualisms, but without the musty weight of tradition and chauvinism that these novels tend to poke fun at. The scattered jokes about the different colleges at Cambridge are lost on this American reader, though I suppose that the most important thing about St. Angelicus--a school Fitzgerald has made up--is that it is tiny. The protagonist of the novel, Fred Fairly, is employed at the college as a lecturer, "assistant organist, assistant librarian, deputy steward, and assist deputy treasurer. The words assistant, deputy, and so forth didn't mean that there was necessarily anyone above him to do the work, only that he must do it without being paid." It also male-only, and as a condition of his employment, Fred has to agree never to marry. You may guess for yourself how what kind of conflict that introduces to the novel for Fred.
Fred has decided that he is an atheist, and feels obligated to tell his father, a small-town rector. His position is teaching science (I think some kind of theoretical physics). Fitzgerald wrings a lot out of the epistemological overlap between science and faith. Fred's mentor, Professor Flowerdew, rails against the theoretical study of the atom, a new study in 1907:
'There will be many apparent results, some useful, some spectacular, some, very possibly, unpelasant. But since the whole basis of the present research is unsound, cracks will appear in the structure one by one. The physicists will begin by constructing models of the atom, in fat there are some very nice ones in the Cavendish at the moment. Then they'll find that the models won't do, because they would only work if atoms really existed, so they'll replace them by mathematical terms which can be stretched to fit. As a result, they'll find that since they're dealing with what they can't observe, they can't measure it, and so we shall hear that all that can be said is that the position is probably this and the energy is probably that. The energy will be beyond their comprehension, so they'll be driven to the theory that it comes and goes more or less at random. Now their hypotheses will be at the beginning of collapse and they will have to pull out more and more bright notions to paper over the cracks and to cram into unsightly corners. There will be elementary particles which are too strange to have anything but curious names, and ant-matter which ought to be there, but isn't. By the end of the century they will have to admit that the laws they are supposed to have discovered seem to act in a profoundly disorderly way. What is a disorderly law, Fairly?'
'It sounds like chaos,' said Fred.
I find this a pretty funny riff on scientific thinking. Fitzgerald, writing in 1990, knows that this is exactly what has happened--the biggest problem in physics today is that our various models of the way things work seem to completely contradict each other. (Though Flowerdew's reference to "anti-matter" tips the hand of the irony a little too far.) But that doesn't invalidate the theoretical structures that Flowerdew wants to reject, and Fitzgerald asks us to apply that to other kinds of thinking and knowing, including the kind of religious tradition that Fred abandons.
At the beginning of the novel, Fred gets into a bicycle crash and falls in love with Daisy, who was riding the other book. Fitzgerald gives Daisy the middle section, which details her career as a nurse. Like many of Fitzgerald's heroines, Daisy is smart and tough, and lives somewhere near the edge of respectable society. Is Fred and Daisy's meet-cute meant to suggest a kind of order that arises out of disorder (the bike crash), and even suggests some divine or otherworldly influence? How about when, at the end of the novel, Daisy--having split from Fred after a formal inquest about the bike crash reveals that she was accompanied by another man--wanders into St. Angelicus, not knowing that Fred works and lies there, only to fortuitously rescue the college's blind old master? The fellows at the college freak out at the presence of a woman, but Fitzgerald suggests that Daisy is able to puncture this insulated, pretentious, narrow-minded, and hyper-masculine space, and that such puncturing is exactly what it needs.