Watson presents an outline of reflections on religion, starting with Greek authors in lecture 1 and closing with Hegel's philosophy of religion in lecture 10. He seeks to demonstrate that religion is co-extensive with the whole realm of human experience.
Lecture 1, “Development of Greek Religion and Theology,” gives an introduction to the object of the first course of lectures. Watson's aim is to trace the influence of philosophy upon the evolution of Christianity. He discusses the supreme principle and the three aspects of religion: belief, ritual, and reverence. Furthermore he expounds the development of the Greek religion and philosophy, discussing the theology of Plato and the theology and philosophy of Aristotle. The theology of the Stoics is examined. The lecture closes with reflections on opposite tendencies in Greek philosophy, which resulted in a conflict between an abstract theism and an equally abstract pantheism, and between a limited conception of social morality and a comprehensive but empty cosmopolitanism.
Lecture 2, “Primitive Christianity and its Exponents,” expounds the development of the Hebrew religion. Watson presents an outline of the religion of Jesus and the early Christian theology. The conflict between Christianity and Judaism, as well as paganism is considered. Doctrines of Gnosticism are examined, among them the doctrines that the sacred writings must not be taken literally, and the God of the Jews was not the true God. Furthermore Watson sheds light on the theology of Marcion, the early Apologists, the epistle of Diognetus and Justin Martyr. The lecture ends with a critical account of the theology of Clement of Alexandria.
In lecture 3, “From Origen to Thomas Aquinas,” Watson starts with the discussion of the philosophical theology of Origen, a pupil of Clement of Alexandria. He continues with his historical reflections on Arius, Athanasius and the Nicene Creed, the theology of Augustine, a history of the Roman church, the theology of Anselm, the rationalism of Abelard, the mysticism of Bernhard of Clairvaux, and the theology of Thomas Aquinas.
Lecture 4 focuses on “Dante's Theology and Politics.” Watson starts with an introduction to the general character of the Middle Ages. The theology of Dante is discussed, as is the politics of Dante, which is based on the idea of one Emperor, one Pope, and one God.
Lecture 5, “Eckhart, Descartes and Spinoza,” is followed by lecture 6, “Leibnitz, Locke and the English Deists.” The reflections on the development of modern philosophy are continued in lecture 7, “Berkeley and Hume,” in which Watson discusses various senses of the term “mind” and “external world.” Furthermore he expounds various theories and conceptions of Berkeley's work, among them the distinction between Berkeley's idealism and objective idealism. In the second part of this lecture he focuses on Hume and his philosophy. The lecture ends with a transition to Kant, the topic of the following lecture 8, “The critical Philosophy.”
Here Watson initially discusses Kant's relation to Leibniz and Hume before going into a more detailed examination of Kant's work. The lecture concludes with a reflection of the doctrines of sin, salvation, the incarnation, justification by faith and Kant's idea of a Church.
In lecture 9 “Hegel's Relation to Kant” is examined. The final lecture (#10) of the first part expounds “Hegel's Philosophy of Religion.” Watson first discusses the general character of Hegelian philosophy. Hegel's reinterpretation of the idea of creation is considered and his philosophy as it is related to the question of the Trinity. Additional topics are the sacraments, the relations of church and state and finally the idea of a philosophy of religion.