Another book-reader adds more criticism:
On the whole, the book is a very solid account of what you term "the conservatism of doubt." Your first principle, that we cannot know the will of the Divine, leads very logically to what I call a theistic libertarianism. That is, in the absence of concrete mandates from God, each person should be free to follow what their own conscience dictates.
You contrast this with fundamentalism, the strain of thought that holds a Divine Truth is knowable, understandable to humans, and (most importantly) permanently applicable to human organization. The book does its best work when it pokes and prods the inconsistencies of this doctrine: you debunk "natural law" as an all-encompassing regimen in a particularly adept passage.
But there are bumps.
When you discuss the political origins of the country, I fear you conflate the objectives and limitations of the nascent federal government with the objectives and limitations of the several states. Yes, it is very true that - as you state on Page 131-132, for example - the U.S. Senate did not hold the new American government to have been founded on Christian religion. But it would be a stretch to apply this same principle to the individual states! At the time of the ratification of the Treaty of Tripoli, the state of Massachusetts was still a legal theocracy. In fact, Massachusetts kept Congregationalism as its established denomination until the 1830s.
So while the federal goverment was, from the outset, designed to be religion-free and kept out of sectarian squabbles, this was not the case for the states. One could go a step further and say the separation of church and state was created at the federal level precisely to preserve the unity of church and state at lower levels. Connecticut didn't want its theocratic preserve overthrown by Virginians, nor did Maryland want its religious laws undone by, say, Vermont.
This is significant because it is the very foundation for the federalist experiment. And here the "conservatism of doubt" has its greatest tension. It must be allied with federalism and the principle that government closest to the ground is best. But can it then allow an unflinching application of this principle? In discussing morals legislation, for example (page 126), you refer to the government's ability to "criminalize private, adult consensual activity," as though 'the government' referred strictly to the federal branch. True, the federal branch does not have - and should not have - the authority to criminalize masturbation, sodomy, or pornography. But it simply doesn't follow that the states are held by identical strictures. Until 2003, as you well know, they weren't.
Under what interpretation, then, would the Lawrence decision - which essentially mooted morals legislation at the state level - be considered one in line with the conservatism of doubt? Can you take away another element of local self-government, as Lawrence did, and still have a functioning federalism? At what point do individual rights, as protected at the federal level, expand to the extent that state governments are non-entities? Apply these same principles to the economic sphere and you have an inkling of the dangers presented: once something is a federal right, local self-determination is gone. At what point does the federal government shoulder such a burden of protecting rights, so conceived, that limited government becomes unworkable?
This unresolved tension leads one to believe that while limited government and federalism are suffering sudden death at the hands of the current Administration, a conservatism of doubt would subject them to the death of a thousand cuts.
I'm really grateful for such a smart and insightful critique. The reader is right that this is a real source of tension in the book and in my own thinking. I've even experienced this as a political actor - in weighing states rights and individual autonomy with respect to marriage equality. My answer, such as it is, is that the federal Supreme Court, as much as the federal government, should be extremely leery of intervening at a state level. My position is Goldwater's.
I guess what I'm saying is that I favor minimal interference with states' rights, and I would prefer even the states to have a minimal interference with individual liberty. Would a conservative of doubt be able to endorse "morals legislation" at a local level? I think so - as long as the laws were reasonably congruent with a reasonable social objective. And the judgment of the reasonableness of such a congruence will vary from state to state and from time to time. What might seem eminently reasonable to one generation may not to the next one. The conservative of doubt will carefully navigate these changing social and cultural waters. The fundamentalist will simply insist an on eternal and unalterable moral order, from which all laws should flow. That's the difference.