As a prelude, I'm going to assume that the facts Barzun claims are vetted carefully by him. I also am going to assume that his statements are on good faith, and by that I mean they are given with the best intentions of complete and accurate depiction of the pertinent facts, except when he indicates one way or the other they are not. This book was clearly written to withstand the scrutiny of the historian elite, and I'll let them quibble over minor factual discrepancies.
First, I would like to point out what seems to me (and I'm borrowing a bit from David here) that he recognizes the importance of Everyman stepping up to the call of history. David pointed this out to me in a discussion about Luther, and I see it again with Calvin:
Contrary to popular belief, Calvin was not fond of power. Generally in poor health, he preferred study and did not repine when in the local struggle, Geneva expelled him.(page 34)I also find it interesting how he portrays the projection of the personalities of both Luthor and Calvin to the masses (top of page 36), as opposed to that in the consensus driven Catholic Church:
The bishops were certainly deliberate: they took 18 years in three bouts of discussion to reach a consensus. It was a providential schedule: old resisters could be gradually argued into their graves (page 38).
I've noticed the same thing in my experiences with startups and large corporations. The startups operate by decree: they must. Money is scarce, and there is little room for dissent. Decisions are made quickly, and all follow. In large corporations, decisions take forever and are consensus based, which is to mean that all stakeholders agree their slice of pie is big enough.
Second, I'm interested in Barzun's use of the analogy "But Calvin--a sort of Lenin to Luther's Marx--may well have saved Protestantism when it was at a low ebb." (page 34). Is it a coincidence that Barzun then spends from the bottom of page 36 to the top of page 38 discrediting two authors who link Protestantism to the origins of Capitalism? This discussion is out of context of the chapter, so clearly he felt it important to include to correct the bias of the commonly held intelligensias' thought that Protestants are responsible for Capitalism. I also suppose he thinks of individualism, the responsibility of each individual for his relation to god, is too much for most people. They would prefer the simpler authoritarian rule, even if it means severe restrictions and penalties. Somewhere, he also points out that Protestantism as a cultural force is fractured, with hundreds of sects. I wonder what Barzun would think if the Catholic church had not existed, but only Lutherns and Calvins. Perhaps the Calvins would be much like the communist countries of the defunct USSR and Maoist China.
Third, I really enjoyed the unexpected and complex interplay between the different religions. From chapter 1, we see that Catholicism begat Protestantism, but Protestantism altered Catholicism in a fundamental way:
it too went to PRIMITIVISM. The aim was to oppose Protestant errors: the result was to freeze Catholic beliefs at the point that European ideas had reached by 1500 or even earlier (bottom of page 39). . .it was these Bible ridden revolutionaries [protestants] who got Galileo condemned for his astronomy (middle of page 40).
I think the answer is that ultimately no one "controls" the future of culture. It is chaotic, and only reflection can unlock the how it happened. I guess that's why we need Barzun.
Finally, I had a fun experience while reading the book. For some reason, I read the quotation by Calving Of Meditating on the Future Life before reading the text. I couldn't make any sense of it. So I read it again. Then again. Perhaps underneath it if there is enough context, it makes sense to someone, but I then read the text next to it and found: "The ailing Calvin was not a relisher; his advice is contradictory and leaves nature a rather narrow crack through which to manifest God's goodness."
As a footnote, I wasn't much attracted to either Calvin or Luther's personalities. They just seem like regular serious folks with their personalities magnified by their opportunity and role in history.