The aftermath of reason

By the early nineteenth century, the Enlightenment’s God of order and law had become a remote abstraction. The universe appeared self-sufficient, the divine architect withdrawn into silence. The question was no longer how to prove God’s existence, but how to live meaningfully in His absence.

Yet the impulse toward unity endured. Where earlier thinkers had sought coherence in theology, the modern mind sought it in nature, history, or humanity. The divine migrated into new symbol, progress, reason, nation, spirit. Monotheism was not destroyed but transposed into immanence.

Romanticism and the immanent divine

The Romantics revolted against the arid rationalism of deism. In the poetry of Wordsworth, the philosophy of Schelling, and the music of Beethoven, the divine re-emerged as presence in nature and emotion.1 Friedrich Schleiermacher recast religion as “the feeling of absolute dependence,” a direct consciousness of the infinite.2

For Hegel, the divine was history itself, Spirit (Geist) unfolding toward self-knowledge. God was realized within contradiction and progress: a historical monotheism, dynamic rather than static.3

The death of God

By mid-century, this immanent unity had thinned into abstraction. Feuerbach declared that God was humanity’s own projected essence; Marx translated that insight into materialism; Nietzsche announced the consequence: *“God is dead … and we have killed him.”*4 His cry was not simple atheism but diagnosis, the moral and metaphysical structure of monotheism had collapsed, leaving a world without inherent meaning. The question once answered by theology, how the One grounds the many, returned as crisis: is there any unity at all?

Science and the mechanical sublime

The transformation of knowledge that began in the eighteenth century was not only mathematical but temporal. Before Darwin, geologists had already discovered that the Earth was vastly older than the few millennia allowed by Scripture. James Hutton, studying the slow cycles of erosion and sedimentation, concluded that the planet showed *“no vestige of a beginning, no prospect of an end.”*5 Charles Lyell, in his Principles of Geology (1830–33), refined this uniformitarianism, revealing an Earth shaped by continuous processes over millions of years, an age that dwarfed Archbishop Ussher’s 4004 BCE creation.6

When Charles Darwin embarked on the Beagle in 1831, he carried Lyell’s first volume. What Hutton and Lyell had discerned in rocks, Darwin saw in life: species, like strata, formed through slow accumulation and selection. Evolution was biology’s version of geology, a theory of time made visible.

The revelation of deep time struck theology as profoundly as heliocentrism had done three centuries earlier. Creation appeared as process rather than event; providence as law working through ages. For some, this enlarged God’s majesty; for others, it erased His immediacy.

By the mid-nineteenth century, the scientific imagination had replaced the medieval hierarchy of angels with the grandeur of natural law. The universe operated by forces requiring no miracle, yet it inspired a new reverence, the mechanical sublime, awe before the immensity of space and the depth of time. The divine had withdrawn, but the sense of unity and order monotheism had bestowed remained, now expressed through the endless creativity of nature itself.

Faith and the problem of mechanism

The new science altered the sense of divine presence. The medieval cosmos had lived by God’s constant will; the Newtonian universe ran by immutable laws. God became the architect whose perfect mechanism required no intervention.

This deistic turn preserved unity but at the cost of intimacy. Descartes, Leibniz, and Spinoza each sought to reconcile mechanism and meaning: Descartes’ God guaranteed reason; Leibniz’s pre-established harmony bound substance to purpose; Spinoza identified God with Nature itself, turning monotheism into philosophical monism.7

Revelation in crisis

The Enlightenment inherited these tensions. Kant’s Religion within the Bounds of Reason Alone transformed revelation into moral autonomy: the law of God became the law of conscience.8 Miracles yielded to ethics, faith to duty. The moral monotheism of reason was the Enlightenment’s final theology, divine command internalized as rational will.

The new sacred order

By the eighteenth century, “Nature” had effectively taken over God’s attributes: universality, regularity, beneficence. Natural law, moral law, and reason formed the secular trinity of the modern world. The cosmos was still one, still intelligible, but revelation came now through observation and experiment. Monotheism had become the conviction that reality itself is lawful.

Continuities

Despite secularization, continuity persisted:

• The belief that truth is one and coherent;

• The assumption that law governs all things;

• The moral intuition of universal human worth.

Modernity did not abolish monotheism; it transposed it. Science, ethics, and politics still bear its imprint, the faith that reason can discern an underlying unity.

Conclusion: the persistence of the One

From the highlands of Iron Age Canaan to the equations of modern cosmology, the history of monotheism traces humanity’s enduring conviction that reality is one and intelligible. Whether named Yahweh, Allah, Reason, or Nature, the quest for unity has ordered both thought and conscience.

Even disbelief inherits that structure. The disenchantment of the world did not end the story of the One; it handed it over to us. The unity once ascribed to God has become the task of humanity itself, to seek coherence within a silent universe.

• 1. William Wordsworth, Lines Composed a Few Miles Above Tintern Abbey (1798); Friedrich Schelling, Philosophical Inquiries into the Nature of Human Freedom (1809).
• 2. Friedrich Schleiermacher, On Religion: Speeches to Its Cultured Despisers (1799).
• 3. G. W. F. Hegel, Phenomenology of Spirit (1807), §808–820.
• 4. Ludwig Feuerbach, The Essence of Christianity (1841); Friedrich Nietzsche, The Gay Science, §125.
• 5. James Hutton, Theory of the Earth (Edinburgh, 1795) I:304.
• 6. Charles Lyell, Principles of Geology (London, 1830–33); James Ussher, Annales Veteris Testamenti (1650).
• 7. Baruch Spinoza, Ethics I–II; G. W. Leibniz, Monadology §§53–62.
• 8. Immanuel Kant, Religion within the Bounds of Reason Alone (1793), Book I.