Lord Herbert aimed for a method of discourse that could settle the bickering between various religious factions by appealing to the fundamental beliefs beneath their competing claims. To get to these foundational matters, Lord Herbert took the necessary step of making an inquiry into the epistemic status of the truth itself. In what is considered to be the first metaphysical work by an English philosopher, De veritate (1624, written in Latin), his longest and most important book, Herbert set out to “to examine truth itself” against those who merely asserted opinions (Scholastics, reformers, and skeptics).34 His investigation confirmed what was true was indeed universal, for “whatever is universally asserted is the truth”; further, it relied on a deity, “for what is universal cannot occur without the influence of the Universal Providence which disposes the movements of events.”35 All of this was derived from our a priori beliefs or “common notions” that our God-given natural instincts allowed us to apprehend.36
With only slight differences in style and emphasis, Grotius and Herbert located the theme of the true in the idea of revelation from God. Their focus on justificatory logic required that the true religion satisfy the standards of abstract philosophy. To defend Christianity on these grounds, they had to recast its ideas of revelation and divine grace as forms of knowledge. Establishing these foundations of Christianity as rational, revealed, and universal (and therefore true) provided Grotius a “good faith” to keep alive “the hope of peace” and Herbert a supreme religion that would “replace all others by including their basic tenets within itself, and by doing so would obviate the need for religious conflict.”37 Philosophic reason—always part mystical (supernatural) and part natural for Grotius and Lord Herbert—had delivered a coherent notion of the universal true religion that comported with our inner worlds and confirmed that human thought proceeded “from the efficiency of that reason impressed upon them, which reason is no other than what we call God.”38
Though Grotius and Lord Herbert tied Christianity more tightly to the idea of the true, the increasing obsession with the method of modern science and concomitant commitment to reason as autonomous and universal in the modern West was largely responsible for pushing philosophical discourse on religion even more deeply into the center of the matrix of scientific truth and knowledge. The illusory ideal of the modern subject as fully autonomous and on a quest for truth as rational certainty through coherence and logical consistency of argument was reflected in the modern conception of religion as a stable philosophical idea. Knowledge, on the logic of abstract thought, was justified purely by proper epistemological commitments. A feature of modern thought that sprung from this way of thinking is the idea that religion was a form of knowledge to be assessed for its validity on the standard of scientific reason. On the modern concept, the genus religion is a bundle of philosophically legitimate beliefs and justifiable practices about God and the world that simply arrived in different species. This theme is evident in a number of moments in discourse on religion, particularly its Enlightenment writings that eloquently treat the tension between philosophical reason and the natural grounds of religion. The work of Matthew Tindal and John Toland, for example, recruited aspects of this modern concept of religion and generally offered true religion as the perfectly rational, completely natural, and thoroughly universal form of Christianity.
The needs of the new self-regulating and self-determining modern subject, the extensive religious warfare and violent factionalism of the late sixteenth and early seventeenth centuries, the further weakening of ecclesiastical theology, and the discoveries of modern science inspired English Enlightenment figures to develop the theme of the true in relation to the natural and moral features of discourse on religion. John Locke’s argument for toleration reflected the Enlightenment quest for a universal ethic. Its effect was to press religious thinkers to deemphasize the concept of revelation, which had served as the central category for Grotius and Lord Herbert. Further, the logic of science and the demands of philosophical reason illuminated two insurmountable problems regarding the concept of revelation: it was neither rationally verifiable nor fully universal. Enlightenment thinkers, therefore, jettisoned the idea of revelation because, on the terms of their enterprise, it mitigated against the possibility that Christianity could be fully established as true.
Secondary literature on eighteenth-century discourse about religion generally contends that religious writings of the early Enlightenment were largely anti-Christian, anticlerical, and antiscriptural. They emphasize that religious discourse in the Enlightenment—counter to that of Grotius and Herbert—was obsessed with establishing scientific reason as foundational for religion, devoted to describing religion as fully natural, and invested in demonstrating the truth of religion from its reflection of nature.39 Though the major texts of this era were not monolithic, this is a fair interpretation of an important strand of Enlightenment writing about religion. The writings of Matthew Tindal and Thomas Morgan are exemplary in this regard: they remained circumscribed by the idea of the true but refused any link to revelation. For them, the true religion was contingent on and marshaled the best of our rational, natural, and moral propensities.40
Tindal’s most well-known work, Christianity as Old as Creation (1730), is written in a quasi-dialogue form between himself and a questioner. Inspired by the work of Cicero, the naturalism of Grotius, and the humanism of Lord Herbert, it further deemphasized the importance of revelation for the true religion. Tindal claimed that revelation was anchored in the particulars of time and place and therefore was too restrictive to be universal. This led to the demotion of the role of revelation in his thought, a watershed move for discourse on religion. Tindal and his deistical cohort undermined revelation not only because they wanted to render a trenchant critique of revealed religion but also because they aimed to put forward a thoroughly universal religious vision that venerated nature, tolerance, and happiness without a personal deity. With revelation—the final impediment to this universal true religion—out of the way, the full burden of human happiness would rest completely on the faculty of unaided human reason. This profound confidence in autonomous reason was derived from the observation of nature for, as Tindal wrote, “the Perfection and Happiness of all rational beings, Supreme as well as subordinate, consists in living up to the dictates of their nature.”41 The laws of nature and reason fully replaced God and revelation as the foundations for the true religion and the sources for human happiness.
Tindal’s recommendation for religion, having shed the baggage of revelation, is, in many ways, a practical, ethical project. Yet he expresses it in terms of religion, not morality, and thereby confirms his aim to be part of the discourse on religion. He writes, “‘true religion’ consist[s] in a constant disposition of mind to do all the Good that we can; and therefore render ourselves acceptable to God in answering the End of his Creation.” It is our duty to embrace the moral demands dictated to us by the “One true religion of mankind,” the “Religion of Nature and Reason written in the hearts of every one of us from the first Creation.”42 The detachment of ethics from religion was left undeveloped in Tindal’s work (as well as Morgan’s), but we can fairly state that Tindal was primarily invested in providing a religious prescription, not simply a moral one.
Following the example of Tindal, Thomas Morgan also saw God’s truth to be evident in the visible, natural world. He too made nature the ultimate standard for religion, deemphasized the role of divine grace, and undermined revelation. Building on the idea ‘true religion’ promoted by Tindal (particularly in Morgan’s most well-known book, The Moral Philosopher [1737], written in dialogue form), Morgan presented a historiography that confirmed true religion as the original religion of humankind that had been corrupted at various stages throughout history. I quote him at length here to show his historical thinking, how he used the idea of nature, and his veneration of the true religion:
The original, true religion, therefore,