The past 150 years have also produced several classifications of religion based on speculative and abstract concepts that serve the purposes of philosophy. The principal example of these is the scheme of Georg Wilhelm Friedrich Hegel, a seminal German philosopher, in his famous Lectures on the Philosophy of Religion (1832). In general, Hegel’s understanding of religion coincided with his philosophical thought; he viewed the whole of human history as a vast dialectical movement toward the realization of freedom. The reality of history, he held, is Spirit, and the story of religion is the process by which Spirit—true to its own internal logical character and following the dialectical pattern of thesis, antithesis, and synthesis (the reconciliation of the tension of opposite positions in a new unity that forms the basis of a further tension)—comes to full consciousness of itself. Individual religions thus represent stages in a process of evolution (i.e., progressive steps in the unfolding of Spirit) directed toward the great goal at which all history aims.

Hegel classified religions according to the role that they have played in the self-realization of Spirit. The historical religions fall into three great divisions, corresponding with the stages of the dialectical progression. At the lowest level of development, according to Hegel, are the religions of nature, or religions based principally upon the immediate consciousness deriving from sense experience. They include: immediate religion or magic at the lowest level; religions, such as those of China and India plus Buddhism, that represent a division of consciousness within itself; and others, such as the religions of ancient Persia, Syria, and Egypt, that form a transition to the next type. At an intermediate level are the religions of spiritual individuality, among which Hegel placed Judaism (the religion of sublimity), ancient Greek religion (the religion of beauty), and ancient Roman religion (the religion of utility). At the highest level is absolute religion, or the religion of complete spirituality, which Hegel identified with Christianity. The progression thus proceeds from human immersed in nature and functioning only at the level of sensual consciousness, to human beings becoming conscious of themselves in their individuality as distinct from nature, and beyond that to a grand awareness in which the opposition of individuality and nature is overcome in the realization of Absolute Spirit.

Many criticisms have been offered of Hegel’s classification. An immediately noticeable shortcoming is the failure to make a place for Islam, one of the major historical religious communities. The classification is also questionable for its assumption of continuous development in history. The notion of perpetual progress is not only doubtful in itself but is also compromised as a principle of classification because of its value implications.

Nevertheless, Hegel’s scheme was influential and was adapted and modified by a generation of philosophers of religion in the Idealist tradition. Departure from Hegel’s scheme, however, may be seen in the works of Otto Pfleiderer, a German theologian of the 19th century. Pfleiderer believed it impossible to achieve a significant grouping of religions unless, as a necessary preliminary condition, the essence of religion were first isolated and clearly understood. Essence is a philosophical concept, however, not a historical one. Pfleiderer considered it indispensable to have conceptual clarity about the underlying and underived basis of religion from which all else in religious life follows. In Die Religion, ihr Wesen und ihre Geschichte (“Religion, Its Essence and History”), Pfleiderer held that the essence of religious consciousness exhibits two elements, or moments, perpetually in tension with one another: one of freedom and one of dependence, with a number of different kinds of relationships between these two. One or the other may predominate, or they may be mixed in varying degrees.

Pfleiderer derived his classification of religions from the relationships between these basic elements. He distinguished one great group of religions that exhibits extreme partiality for one over against the other. The religions in which the sense of dependence is virtually exclusive are those of the ancient Semites, the Egyptians, and the Chinese. Opposite these are the early Indian, Germanic, and Greek and Roman religions, in which the sense of freedom prevails. The religion of this group may also be seen in a different way, as nature religions in the less-developed cultures or as culture or humanitarian religions in the more advanced. A second group of religions exhibits a recognition of both elements of religion, but gives them unequal value. These religions are called supernatural religions. Among them Zoroastrianism gives more weight to freedom as a factor in its piety, and Brahmanism and Buddhism are judged to have a stronger sense of dependence. The last group of religions is the monotheistic religions: Islam, Judaism, and Christianity, which are divided again into two sub-groups, i.e., those that achieve an exact balance of the elements of religion and those that achieve a blending and merging of the elements. Both Judaism and Islam grant the importance of the two poles of piety, though there is a slight tendency in Islam toward the element of dependence and in Judaism toward freedom. It is Christianity alone, he claimed, that accomplishes the blending of the two, realizing both together in their fullness, the one through the other.

The intellectual heritage that lies behind this classification will be immediately apparent. The classification reflects its time (19th century) and place (western Europe) of conception in the sense that the study of religion was not yet liberated from its ties to the philosophy of religion and theology.