A basic contrast between German and French Enlightenment theology can be seen in a comparison of Lessing and Rousseau. Lessing understands religious belief to have use-value as a set of doctrinal, revelatory truths that aid the believer in attaining the indelible truths of Reason. Revelation is useful in that it can hurry up the process of Reason’s promised progression of humanity. In a way, it is akin to how Sunday schools use flannel-graphs to teach children the “elementary truths” of the Old Testament. For Lessing, the Old Testament was a shadow of the New, and so the New Covenant is but a shadow of the Eternal Gospel that is yet to come. However, we are warned to not be too hasty in proclaiming the Eternal Covenant, for there is still much to gleam from the second primer of Christ yet at hand.
At the other end, Rousseau rejects any kind of progressivist notion in favor of a more chronologically universal (as opposed to Lessing’s universalism of breadth) reading of religion. Rousseau begins the dialogue with the Savoyard priest with a conspicuously Cartesian methodology. He doubts all traditions, all histories, and all contingent truths that have been given to him in favor of the pure “state of nature” found in the human conscience. An early Romanticism is often linked to Rousseau, yet it is not the natural realm itself that is divinized, but the inner state of man. It is feelings, and intuition that are thought to be self-evidently true. In this way, true religion is available to all, irrespective of context, for all men are front-loaded with the hardware necessary for communion with God.
The main contrasts are in the divergent views of history. For Rousseau, history is useless, for it is complicit in the corruptions that society have wrought upon the innocence of conscience; whereas, for Lessing, history is the domain of revelation, that, while simply being a means to the end of Reason’s ultimate triumph, is still an instrumental necessity. Here we see a philosophical trajectory that both nations will follow into the 20th century: Lessing’s vision of a religious revelation with utility (albeit a small one) comes to full bloom in the Hegelian notion of the Absolute Spirit; and the emphasis upon translation of revelatory contingencies into properly Reason-able categories is seen in the project of Jurgen Habermas. Meanwhile, Rousseau’s distaste for the perichoretic nature of humanity, in favor of a strict religious individualism divested of all inter-subjective distortion, comes to a fiery end in Sartre’s dictum: “Hell is other people”.