In the first set of lectures contained in The Evolution of Religion, vol. 1, Caird endeavours to establish religion as one of the great factors or elements in our conscious life. More specifically, he tries to show that, just as a consciousness of the object and the subject, of the world without and the self within, must be supposed to exist in all rational beings, so in all rational beings there is at least a dawning consciousness of the unity presupposed in this difference, of the universal which originates and transcends this elementary distinction of our life.
At the outset of The Evolution of Religion, vol. 2, Caird then contrasts the two forms of objective and subjective religion. Next, as in first volume, Caird speaks of the Jewish religion as a religion of subjectivity. He also shows how the development of goodness was seen to involve an inward struggle with the natural self and an outward discipline of suffering and sacrifice. And, as this process became established, it put a greater distance between the joy to be earned from the harmony of the soul with itself and God.
Caird then places Judaism in relation to Christianity, and, in turn, to Buddhism. He points out that in Buddhism, Spirit absolutely excludes nature, and in Judaism, it dominates nature. In Christianity, however, Spirit is the highest manifestation of the same principle revealed in nature. In Christianity, then, there is a union of monotheistic and pantheistic ideas. Difficulties, though, arise from this synthesis. Caird presents a solution: organic unity and evolution.
From the relation of Judaism to Christianity and Buddhism, the author moves to the problem of later Judaism, the answer of Jesus and the difficulty in which subjective religion ends. Given the presence and work of Jesus, Caird contends that Christianity at once realized and transcended, fulfilled and abolished the religion of Israel. God, then, becomes the God of all humankind and all nations, the God who is revealed in nature and history alike. The spiritual idea of God which, in Jewish monotheism, had been reached by the harsh breach of his connection with nature and with humankind, is retained. In place of the purely negative elevation of the Divine Subject above all objects in the finite world, however, we have a positive idea of God as a spiritual principle manifested in the organic unity of that world with all its differences. The cross, then, serves as the point in the process of evolution whereby all these differences are reconciled and overcome.
While Caird summarizes the general purport of the teaching of Jesus and shows how the events of his life and death were the most vivid and palpable demonstration of the lesson he had to teach, he also indicates that St Paul was the first who went beyond the special words and actions of the Master and grasped that lesson in all the extent of its application. Thus, as Caird argues, St Paul emancipated Christianity from the limitations of Judaism and from all the special conditions of its first expression.
The author next considers the way in which St Paul at once generalizes and idealizes the faith of Christ, liberating it from the Judaic conditions of its origin, and at the same time lifting it into the region of theology. For Paul, the whole of the life of Christ became summed up in his death, and the story of his humanity was changed into the history of a divinely commissioned Messiah. Paul maintained that through Christ’s death a new principle has been introduced into humanity—a principle which, in everyone who has faith in Christ, will produce the same fruits as are in him.
From discussion of St. Paul, Caird moves, in chapter 9, to the Gospel of John and the idea of a divine humanity. He points out that the idealizing process that follows death is not necessarily a fictitious process of imagination and that the growing powers of man are often best revealed in their results beyond the life of the individual. According to the author, Christianity provides the highest example and explains the rationale of this process.
Having surveyed Pauline and Johannine thought, Caird discusses the general characteristics of the evolution of Christianity in post-apostolic times. While he notes that the New Testament contains all the germinal ideas of Christianity, he also underscores the limitations of this statement. He then examines how far Christianity is opposed to the religion and culture that existed before it; specifically, how far its development is a conquest and how far it is an assimilation of foreign elements. In short, Caird highlights Christianity’s struggle with Jewish and Greek influences and explicates what makes it original and unique.
The development of Christianity before the Reformation provides the content of the following chapter, in which Caird contrasts periods before and after the Reformation and examines their respective relations to the Christianity of the New Testament. Within such an examination of contrasts, the author notes the revival of the tendencies of objective religion as well as the tendency to abstraction in theory and asceticism in the practice of the early church, and the influences of Jewish and Greek thought upon it. The effect of the invasion of the Barbarians, scholastic philosophy and mysticism also receive attention.
In closing, Caird considers the development of Christianity after the Reformation. He understands Protestantism as a subjective religious movement and the Protestant gospel as the gospel of freedom. He explores the Protestant tendency to get rid of the objective element of religion and conflict with the opposite principle in Roman Catholicism. In recent times, Caird argues that the movement is toward a reconciliation of the two great tendencies of religion. Finally, in closing, he notes the hindrances and aids to faith in the present day, 1891–1892.