This book is so rich in powerful argument, profound insight, and deep scholarship that I cannot, in a brief review, do any real justice to it. What I can do is indicate the central propositions the book defends (with great success, in my opinion) in the hopes that doing so will tempt others to read it themselves.
As the subtitle of the book indicates, one of the chief inspirations of Reitan's philosophical theology is Friedrich Schleiermacher, whose celebrated Speeches on Religion to its Cultured Despisers founded what Karl Barth called a new epoch in Christian thought. In fact Schleiermacher is commonly (and rightly) regarded as the father of the liberal theology of the 19th century, a kind of theology that has, unfortunately, been eclipsed (especially in popular culture) by the reactionary "primitivized Orthodoxy' (to borrow and apt phrase of Tillich) commonly known as fundamentalism. The theology of Schleiermacher, like that of Aquinas and Leibniz (both of whom have also influenced Reitan), was informed by deep learning and profound philosophical thought. This, however, is true of all the greatest theology of the Christian Church, from St. Augustine to Wolfhart Panneberg. What separates Schleiermacher from most theologians who came before him and after him, is the emphasis he placed on what he took to be the root of theology, something he describes in the Speeches as "the intuition of the infinite in the finite". This intuition or sense (or feeling), an intuition that might be called "mystical", is not to be confused with the interpretations of the world, the self, or God which might be developed out of it. And, as Reitan carefully explains in chapter 1 of his book, this intuition, which IS piety according to Schleiermacher, and is also the basis of religious thought, (i.e. conceptualizations of reality in light of it) is, by its very nature, inclusive. It is inclusive because the infinite, by ITS nature, is inclusive of the finite as ground and cause, and so any living sense of the infinite will drive us out of ourselves into union with the other finite beings which are sustained in the bosom of the infinite. Furthermore, any living intuition of the infinite leads to the awareness that, however carefully we may work out a theology based on this intuition (and all who have read Schleiermacher's systematic theology know how carefully and how rigorously he worked out his theology), we can never exhaust it and so must be glad, nay eager, to listen to others who have had an experience of the infinite, even if they interpret it differently. Thus for Schleiermacher, as for his student Reitan, any form of religion that thunders anathamas at the sincerely held religious doctrine of others, or that seeks to use religion as a pretext for violence, is not real religion at all, but a corruption of it. Reitan works out Schleiermacher's profound train of thought here with great care and vigor and, in so doing, shows that the moral attacks made on religion by contemporary cultured despisers of it miss their target, even as the cultured despisers of Schleiermacher's day did. What they attack, in fact, is not religion but its corruption.
In the second chapter of his book Reitan shows that the cultured despisers of religion mistake the good God of theism with the idol of superstition. Reitan does admit that many second and third rate "theologians' are partially to blame for this since may of them do not worship a God who could be called good in any meaningful sense, but rather an idol who rules tyranically over the universe, ready to strike down all those who these "theologians" dislike (e.g. gays, heretics, atheists, liberals, etc.) In this chapter Reitan brilliantly appropriates the thought of Plutarch and Zoroaster (the ancient Persian Prophet who founded the now nearly dead Zoroastrian religion) to argue for the proposition that only a being worthy of worship could truly be called "God", and that goodness, understood as the creative and preserving power of love, is the most important of all "God making" properties.
In chapter 3 Reitan continues his assault on the God of superstition by attacking both the divine command theory of ethics, a theory that emphasizes God's power to the point of robbing the term "good" of all meaning, as well the literalist interpretation of Scripture championed by fundamentalists, an interpretation that falsely seeks to rob the human being of the right, nay the duty, to use what his reason tells him about the ethical to test the truth of all purportedly revealed moral doctrines.
In the next two chapters Reitan defends Aquinas's and Leibniz's cosmological proofs for God's existence from certain misguided attacks on them. Reitan does not, in these chapters, attempt to defend, or even explain, Aquinas's and Leibniz's arguments for the conclusion that there is only ONE uncaused cause of all other beings, and that this cause is the all good, all knowing, and all powerful God of theism, contenting himself with the more modest claim that their arguments for the existence of an uncaused and necessary being make it rational to believe that the empirical world is sustained in existence by a being which transcends it. In this way Reitan seeks to strengthen the case for the veridicality of Schleiermacher's intuition of an infinite being lying behind and within all finite beings.
In the 7th chapter of his book Reitan examines religious consciousness, noting that many persons besides Schleiermacher have had mystical experiences of an infinite being. He also, in this chapter, is at pains to note that there are different kinds of mystical experience (relying here, in part, on the celebrated studies of James an Zaehner) and also that different people may, quite reasonably, interpret experiences of the same sort in different ways. Sam Harris is a particular target of Reitan's keen dialectic in this chapter since Harris arrogantly asserts, without argument, that all true mystical experience will attest to the truth of the Buddhist "no self" doctrine. Relying on both Lotze and Schleiermacher Reitan presents powerful arguments for the proposition that the sense of the loss of self that many mystics report can just as reasonably (or perhaps more reasonably) be given a theistic interpretation as a Buddhist one, and that such an interpretation is closed only to those who dogmatically insist that the good God of theism is an illusion.
In chapter 8 of his book Reitan explicates and defends a Lutheran interpretation of faith as trust in a good God who delivers human beings from sin and death, and he shows that this trust, if it is to be true to itself, cannot be used as a pretext to persecute homosexuals, or heretics, or atheists, etc. Reitan further shows that such a trust is eminently reasonable (even thought not rationally irresistible) and that it has nothing in common with believing in Santa Clause or fairies.
In chapter 9 Reitan confronts the problem of evil, admitting that, while there are insights to be gained from many of the classical Christian theodices, none has really solved the problem. But he argues, persuasively, that this fact is no more sufficient to make faith in a good God irrational than the fact that biologists have not solved certain problems facing the theory of evolution makes it irrational to continue to believe in that theory.
Finally, in the last chapter of the book Reitan launches into a stinging attack on those who insist that religion is the cause of all the greatest evils in the world. Reitan shows that certain far from admirable traits of the human mind (e.g. a need for absolute certainly, a laziness in the face of the daunting task of creating a truly just society, a fear of the other, etc.) can, if unchecked, lead humans to an ideology with divides the world into the children of light and the children of darkness. Religion can, and has, been used as a way of achieving this division, but as Reitan correctly notes, so have race, ethnicity, nationality, sexual orientation, etc. And these things, unlike religion, have no inherent power to say "No" to the tribalism that so often takes possession of mankind. Religion, however, if it is true to itself, does have such power since it is rooted in the intuition that there is an infinite good that is present in, with, and under all finite beings.
This book is a gem and I fancy that in writing it Reitan has made his 19th century guru both happy and proud.