Rationalism (Latin, ratio—reason, the faculty of the mind which forms the ground of calculation, i.e. discursive reason. See Apologetics; Atheism; Bible; Deism; Empiricism; Biblical Exegesis; Faith; Materialism; Miracle; Revelation). The term is used: (I) in an exact sense, to designate a particular moment in the development of Protestant thought in Germany; (2) in a broader, and more usual, sense to cover the view (in relation to which many schools may be classed as rationalistic) that the human reason, or understanding, is the sole source and final test of all truth. It has further: (3) occasionally been applied to the method of treating revealed truth theologically, by casting it into a reasoned form, and employing philosophical categories in its elaboration. These three uses of the term will be discussed in the present article.
The German school of theological Rationalism formed a part of the more general movement of the eighteenth-century "Enlightenment". It may be said to owe its immediate origin to the philosophical system of Christian Wolff (1679-1754), which was a modification, with Aristotelean features, of that of Leibniz, especially characterized by its spiritualism, determinism, and dogmatism. This philosophy and its method exerted a profound influence upon contemporaneous German religious thought, providing it with a rationalistic point of view in theology and exegesis. German philosophy in the eighteenth century was, as a whole, tributary to Leibniz, whose "Theodicee" was written principally against the Rationalism of Bayle: it was marked by an infiltration of English Deism and French Materialism, to which the Rationalism at present considered had great affinity, and towards which it progressively developed: and it was vulgarized by its union with popular literature. Wolff himself was expelled from his chair at the University of Halle on account of the Rationalistic nature of his teaching, principally owing to the action of Lange (1670-1774; cf. "Cauca Dei et religionis naturalis adversus atheismum", and "Modesta Disputatio", Halle, 1723). Retiring to Marburg, he taught there until 1740, when he was recalled to Halle by Frederick II. Wolff's attempt to demonstrate natural religion rationally was in no sense an attack upon revelation. As a "supranaturalist" he admitted truths above reason, and he attempted to support by reason the supernatural truths contained in Holy Scripture. But his attempt, while it incensed the pietistic school and was readily welcomed by the more liberal and moderate among the orthodox Lutherans, in reality turned out to be strongly in favor of the Naturalism that he wished to condemn. Natural religion, he asserted, is demonstrable; revealed religion is to be found in the Bible alone. But in his method of proof of the authority of Scripture recourse was had to reason, and thus the human mind became, logically, the ultimate arbiter in the case of both. Supra-naturalism in theology, which it was Wolff's intention to uphold, proved incompatible with such a philosophical position, and Rationalism took its place. This, however, is to be distinguished from pure Naturalism, to which it led, but with which it never became theoretically identified. Revelation was not denied by the Rationalists; though, as a matter of fact, if not of theory, it was quietly suppressed by the claim, with its ever-increasing application, that reason is the competent judge of all truth. Naturalists, on the other hand, denied the fact of revelation. As with Deism and Materialism, the German Rationalism invaded the department of Biblical exegesis. Here a destructive criticism, very similar to that of the Deists, was levelled against the miracles recorded in, and the authenticity of the Holy Scriptures. Nevertheless, the distinction between Rationalism and Naturalism still obtained. The great Biblical critic Semler (1725-91), who is one of the principal representatives of the school, was a strong opponent of the latter; in company with Teller (1734-1804) and others he endeavored to show that the records of the Bible have no more than a local and temporary character, thus attempting to safeguard the deeper revelation, while sacrificing to the critics its superficial vehicle. He makes the distinction between theology and religion (by which he signifies ethics).
The distinction made between natural and revealed religion necessitated a closer definition of the latter. For Supernaturalists and Rationalists alike religion was held to be "a way of knowing and worshipping the Deity", but consisting chiefly, for the Rationalists, in the observance of God's law. This identification of religion with morals, which at the time was utilitarian in character (see Utilitarianism), led to further developments in the conceptions of the nature of religion, the meaning of revelation, and the value of the Bible as a collection of inspired writings. The earlier orthodox Protestant view of religion as a body of truths published and taught by God to man in revelation was in process of disintegration. In Semler's distinction between religion (ethics) on the one hand and theology on the other, with Herder's similar separation of religion from theological opinions and religious usages, the cause of the Christian religion, as they conceived it, seemed to be put beyond the reach of the shock of criticism, which, by destroying the foundations upon which it claimed to rest, had gone so far to discredit the older form of Lutheranism. Kant's (1724-1804) criticism of the reason, however, formed a turning-point in the development of Rationalism. For a full understanding of his attitude, the reader must be acquainted with the nature of his pietistic upbringing and later scientific and philosophical formation in the Leibniz-Wolff school of thought (see Immanuel Kant). As far as concerns the point that occupies us at present, Kant was a Rationalist. For him religion was coextensive, with natural, though not utilitarian, morals. When he met with the criticisms of Hume and undertook his famous "Kritik", his preoccupation was to safe-guard his religious opinions, his rigorous morality, from the danger of criticism. This he did, not by means of the old Rationalism, but by throwing discredit upon metaphysics. The accepted proofs of the existence of God, immortality, and liberty were thus, in his opinion, overthrown, and the well-known set of postulates of the "categoric imperative" put forward in their place. This, obviously, was the end of Rationalism in its earlier form, in which the fundamental truths of religion were set out as demonstrable by reason. But, despite the shifting of the burden of religion from the pure to the practical reason, Kant himself never seems to have reached the view—to which all his work pointed—that religion is not mere ethics, "conceiving moral laws as divine commands", no matter how far removed from Utilitarianism—not an affair of the mind, but of the heart and will; and that revelation does not reach man by way of an exterior promulgation, but consists in a personal adaptation towards God. This conception was reached gradually with the advance of the theory that man possesses a religious sense, or faculty, distinct from the rational (Fries, 1773-1843; Jacobi, 1743-1819; Herder, 1744-1803,;—all opposed to the Intellectualism of Kant), and ultimately found expression with Schleiermacher (1768-1834), for whom religion is to be found neither in knowledge nor in action, but in a peculiar attitude of mind which consists in the consciousness of absolute dependence upon God. Here the older distinction between natural and revealed religion disappears. All that can be called religion—the consciousness of dependence—is at the same time revelational, and all religion is of the same character. There is no special revelation in the older Protestant (the Catholic) sense, but merely this attitude of dependence brought into being in the individual by the teaching of various great personalities who, from time to time, have manifested an extraordinary sense of the religious. Schleiermacher was a contemporary of Fichte, Schelling, and Hegel, whose philosophical speculations had influence, with his own, in ultimately subverting'Rationalism as here dealt with. The movement may be said to have ended with him—in the opinion of Teller "the greatest theologian that the Protestant Church has had since the period of the Reformation". The majority of modern Protestant theologians accept his views, not, however, to the exclusion of knowledge as a basis of religion.
Parallel with the development of the philosophical and theological views as to the nature of religion and the worth of revelation, which provided it with its critical principles, took place an exegetical evolution. The first phase consisted in replacing the orthodox Protestant doctrine (i.e. that the Sacred Scriptures are the Word of God) by a distinction between the Word of God contained in the Bible and the Bible itself (Tollner, Herder), though the Rationalists still held that the purer source of revelation lies rather in the written than in the traditional word. This distinction led inevitably to the destruction of the rigid view of inspiration, and prepared the ground for the second phase. The principle of accommodation was now employed to explain the difficulties raised by the Scripture records of miraculous events and demoniacal manifestations (Senf, Vogel), and arbitrary methods of exegesis were also used to the same end (Paulus, Eichhorn). In the third phase Rationalists had reached the point of allowing the possibility of mistakes having been made by Christ and the Apostles, at any rate with regard to non-essential parts of religion. All the devices of exegesis were employed vainly; and, in the end, Rationalists found themselves forced to admit that the authors of the New Testament must have written from a point of view different from that which a modern theologian would adopt (Henke, Wegscheider). This principle, which is sufficiently elastic to admit of usage by nearly every variety of opinion, was admitted by several of the Supernaturalists (Reinhard, Storr), and is very generally accepted by modern Protestant divines, in the rejection of verbal inspiration. Herder is very clear on the distinction—the truly inspired must be discerned from that which is not; and de Wette lays down as the canon of interpretation "the religious perception of the divine operation, or of the Holy Spirit, in the sacred writers as regards their belief and inspiration, but not respecting their faculty of forming ideas..." In an extreme form it may be seen employed in such works as Strauss's "Leben Jesu", where the hypothesis of the mythical nature of miracles is developed to a greater extent than by Schleiermacher or de Wette.
(2) Rationalism, in the broader, popular meaning of the term, is used to designate any mode of thought in which human reason holds the place of supreme criterion of truth; in this sense, it is especially applied to such modes of thought as contrasted with faith. Thus Atheism, Materialism, Naturalism, Pantheism, Scepticism, etc., fall under the head of rationalistic systems. As such, the rationalistic tendency has always existed in philosophy, and has generally shown itself powerful in all the critical schools. As has been noted in the preceding paragraph, German Rationalism had strong affinities with English Deism and French Materialism, two historic forms in which the tendency has manifested itself. But with the vulgarization of the ideas contained in the various systems that composed these movements, Rationalism has degenerated. It has become connected in the popular mind with the shallow and misleading philosophy frequently put forward in the name of science, so that a double confusion has arisen, in which (i) questionable philosophical speculations are taken for scientific facts, and (ii) science is falsely supposed to be in opposition to religion. This Rationalism is now rather a spirit, or attitude, ready to seize upon any arguments, from any source and of any or no value, to urge against the doctrines and practices of faith. Beside this crude and popular form it has taken, for which the publication of cheap reprints and a vigorous propaganda are mainly responsible, there runs the deeper and more thoughtful current of critical-philosophical Rationalism, which either rejects religion and revelation altogether or treats them in much the same manner as did the Germans. Its various manifestations have little in common in method or content, save the general appeal to reason as supreme. No better description of the position can be given than the statements of the objects of the Rationalist Press Association. Among these are: "To stimulate the habits of reflection and inquiry and the free exercise of individual intellect... and generally to assert the supremacy of reason as the natural and necessary means to all such knowledge and wisdom as man can achieve". A perusal of the publications of the same will show in what sense this representative body interprets the above statement. It may be said finally, that Rationalism is the direct and logical outcome of the principles of Protestantism; and that the intermediary form, in which assent is given to revealed truth as possessing the imprimatur of reason, is only a phase in the evolution of ideas towards general disbelief. Official condemnations of the various forms of Rationalism, absolute and mitigated, are to be found in the Syllabus of Pius IX.
(3) The term Rationalism is perhaps not usually applied to the theological method of the Catholic Church. All forms of theological statement, however, and pre-eminently the dialectical form of Catholic theology, are rationalistic in the truest sense. Indeed, the claim of such Rationalism as is dealt with above is directly met by the counter claim of the Church: that it is at best but a mutilated and unreasonable Rationalism, not worthy of the name, while that of the Church is rationally complete, and integrated, moreover, with super-rational truth. In this sense Catholic theology presupposes the certain truths of natural reason as the preambula fidei, philosophy (the ancilla theologice) is employed in the defense of revealed truth (see Apologetics), and the content of Divine revelation is treated and systematized in the categories of natural thought. This systematization is carried out both in dogmatic and moral theology. It is a process contemporaneous with the first attempt at a scientific statement of religious truth, comes to perfection of method in the works of such writers as St. Thomas Aquinas and St. Alphonsus, and is consistently employed and developed in the Schools.