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A theory or system that exaggerates reason's independence from the senses in philosophy or from supernatural revelation in religion. Although it appears in many forms, in nearly all a doctrinaire insistence on the sovereignty of reason displaces a native trust in the reasonableness of human thought, and an arbitrary insistence is placed on the former as uniquely representative of free scientific inquiry. This article treats first of philosophical rationalism, giving its historical outline and characteristics, and then of religious rationalism, both negatively as denying the supernatural and affirmatively as an aid to understanding revealed truth.

Philosophical Rationalism

Philosophical rationalism is commonly associated with certain philosophers of the 17th and 18th centuries in Continental Europe, notably R. descartes, B. spinoza, and G. W. leibniz. Generally it holds that reason rather than sense experience is the source of knowledge and the ultimate test of truth. Its opposite is empiricism or positivism, which maintain that ideas and propositions not directly verifiable by sensory observation are meaningless. Usually rationalistic knowledge is thought to originate in reason itself, being a system of universal and necessary truths based on principles or starting points not discovered in experience.

As an attitude of mind resulting from philosophical positions, rationalism tends to single out and magnify abstract human reason while minimizing other human powers, such as sense, imagination, and free will. Logical ideals of order, procedure, and method predominate over empirical data and experimental technique. As a philosophical position, rationalism usually involves the following theories relating to being and knowledge, methodology, and sufficient reason.

Being and Knowledge. Most rationalist systems rest on Plato's theory of a dual universe, wherein eternal, necessary truths somehow exist apart from the world of human experience but remain accessible to human reason. This concept of a "duoverse" was further developed by Descartes, who considered material substances or extended bodies in mechanical motion as independent units, distinct and separate from spiritual substance or thinking mind. Even in man, the meeting place of the two realms of body and spirit, this separation held.

Hence, for neither Plato nor Descartes could the material world of sense experience be a source of genuine knowledge. Adopting a theory of innate ideas, Plato's epistemological rationalism held that human reason had "seen" in a previous existence the necessary and eternal truths. By recollection of these ideas, the mind obtains real knowledge even though it is surrounded by a shadow world of change that is basically unintelligible. Plato's Socratic dictum, "Virtue is knowledge," also founded a type of ethical rationalism.

Descartes's theory was more complex and did not involve the Platonic notion of recollection. He thought of the human mind as born with the materials of knowledge, e.g., certain fundamental concepts such as "God," "being," "soul," "material substance," "cause," "number," "time," "space," and "motion," as well as general propositions such as "I think, therefore I am"; "Every event has a cause"; and "God is perfect and cannot deceive me." These, as well as the basic truths of ethical obligation, are discovered in the mind itself and not in extramental reality, even though experience may help clarify and make explicit what the mind contains (see innatism). Derided by empiricists as empty a priori forms, these, for the rationalist, were the starting points of deductive movements of the mind toward further truths, including the results of applying universal concepts to empirical data. Descartes, for instance, could build on them an argument for the existence of a material world otherwise not known with certainty to exist. For him, the truths of faith were not among the certitudes of reason, but depended rather on the willa position designed to safeguard the supernatural but later to lead to religious rationalism and the denial of revealed truth.

Some types of rationalism admit that ideas are supplied to reason either from sense experience or in self-reflection. Reason, however, still functions to discover real knowledge by seeing relations and necessary connections or by deducing further consequences from the resulting intelligibility. Some rationalists think of reason as an instrument for bridging the gap between itself and reality. For them, knowledge is attained by applying to experience concepts or meanings discovered in reason. Characteristic of all such rationalism is the tendency to view ideas or concepts rather than things themselves as the objects of thought. For thinkers such as I. kant and G. W. F. hegel, the gap between the meanings of reason and the things of experience stimulated a critical rationalism that ultimately reduced all of reality to reason and absolute mind.

Besides attempting to deduce from fundamental laws of logic the basic propositions of a universal system of knowledge, Leibniz developed a rationalist theory that depended explicitly on the existence and functioning of an infinite intelligence.

Methodology. Mathematics, with its clear and distinct ideas and rigorous demonstration, was the ideal knowledge and method for most rationalists. Seventeenth-century scientists such as J. kepler, G. galilei, and, later, I. Newton devised physical theories that were heavily mathematical in character. As their new and powerful method for describing the physical universe was perfected, philosophers tried to introduce the rigor of mathematics into every department of knowledge. H. grotius is a good example of this, with his secularization of law. As rationalists, these thinkers tended to narrow their conception of genuine knowledge to that obtained by the methods of physical science, restricted though these may have been.

Spinoza and Leibniz exemplify attempts to solve a crucial problem that immediately came into focus, namely, how to use such methods to construct a rationalistic system that could embrace mind and God as well as matter. Boundless confidence in the power of reason for a time overcame the natural repugnances these systems encountered from common sense. In the end there was no escaping the fact that such methods had nothing to say about the meaning of man, of human values, and of freedom, none of which exhibit mechanical or mathematical characteristics.

But some popularizers of the new learning unreasonably concluded that what these methods could not treat did not exist, and they somehow won for themselves the title of rationalists, combining a valid rejection of prejudice, ignorance, credulity, and superstition with an irrational rejection of revelation and religious authority.

Others refused to straitjacket the mind in the mathematical-physical method, and kept philosophy open to genuine knowledge of man, God, and freedom. This tension continued into the 18th-century Age of the Enlightenment, with its practical applications of rationalism to questions of authority in religion, theories of government in politics, and further developments of method in science. In the common confusion between philosophical rationalism and the new scientific methods, older philosophers and overzealous Churchmen, conscious of the philosophical errors in rationalism, condemned the new science as erroneous philosophy and acted at times to interfere with free scientific inquiry.

Sufficient Reason. One of Leibniz's followers, C. wolff, sought to advance philosophical knowledge by transferring the new ideals of method and some of its nonphilosophical procedures into metaphysics, philosophy of man, and ethics. He accepted Leibniz's distinction between "truth of fact" and "truth of reason," and made extensive use of the principle of sufficient reason to transform all contingent elements to rational elements, thus attempting to bridge the chasm between experience and reason. This resulted in a rationalistic system wherein each form of empirical knowledge, such as physics or psychology, was supplemented by a corresponding rational form that functioned to raise the former to the level of genuine knowledge by deducing it from the principles of general ontology and cosmology.

Wolff's voluminous work was condensed into handy manuals by his followers, who embodied his basic rationalistic view of a duoverse and the deductive ideal of a system of knowledge. These were widely used in Protestant seminaries and universities and became well known to scholastics. Philosophy textbooks modeled on Wolff's were produced by German Jesuits between 1750 and the suppression of the Society of Jesus (1773), and the work was continued by Franciscans and others who imitated Wolff's scholasticism. Catholic manual writers were to come under the influence of such German rationalism as late as the 20th century. In the absence of adequate historical studies of scholasticism at the time, this type of rationalism was considered to be genuinely scholastic and led many to accept its demolition by Kant as a final destruction of scholastic philosophy [see J. E. Gurr, The Principle of Sufficient Reason in Some Scholastic Systems, 17501900 (Milwaukee 1959)]. Many theology manuals followed a similar method, beginning with definitions of theological realities and then seeking a greater insight by relating concepts or by analyzing definitions to discover their full logical implications.

Kant, who was nurtured on this kind of philosophical rationalism, set out to destroy it; at the same time he wished to safeguard ultimate truths about man and God with a new critical, as opposed to a dogmatic, rationalism. His attempts to remove such truths from the sphere of reason, howeversince they neglected the native, spontaneous reasoning powers of the human mindactually dissolved the rational basis of faith and morals and led eventually to advanced forms of religious rationalism.

Religious Rationalism

Religious rationalism has both a philosophical and a social dimension. As derived from philosophical rationalism, it is a negative and limited view of reason as supremely competent in matters of faith and morals. Thus it holds that an adequate theory of man, of his relations with God, and of his destiny can be had from human intelligence alone; it thereby excludes revelation and the evidence of any authoritative witness. As resulting from the positive use of reason to penetrate, understand, and defend truths known by faith, religious rationalism is a form of theological activity.

Negative Aspect. Early Greek thinkers who rejected explanations of the world of experience in terms of the gods and goddesses of mythology to substitute the principles and causes of philosophy were rationalists without being antireligious. Rationalist elementsin the sense of questioning existing institutions and ways of doing or thinking, or of criticizing abuses, real or imaginedare present in the oldest Biblical documents.

But modern religious rationalismfrom the Averroists of the late Middle Ages, through the humanists of the Reformation and the philosophes of the Enlightenment, to 20th-century evolutionistsmutilates by its negations the power of reason to range beyond finite personality and the natural world. The present narrow form of this doctrine is scientism, which teaches that the natural sciences study all of reality and that their methods are the only valid way to knowledge.

As involving practical conflicts between Church authorities and those who confuse scientific method with metaphysics, rationalism is itself an ideology finding expression in a sustained war on prevailing creeds and institutions, whether these be Catholic, Protestant, or Jewish. English deists such as J. locke, whose influence still is felt in freemasonry, and French encyclopedists such as P. bayle and voltaire personify this ideology. These men were committed to eliminating from Christianity, in the name of sovereign reason, whatever was above human comprehension. Biblical accounts of creation, God's dealings with the Jews, miracles, the Incarnation, the Resurrection, prayer, providence, and a divine teaching authority in the Church were all refused credence. In Germany and France the enlightenment (Ger. Aufklärung, or clearing up) aimed at banishing all mystery and the supernatural, specializing in the application of restricted standards of reason to art, literature, and political and social activity. On Nov. 10, 1793, this practical doctrinaire rationalism culminated in the French National Convention's selecting a Madame Maillard to represent the goddess of reason and enthroning her in the Cathedral of Notre Dame in Parisdesignated for a time as the Temple of Reason.

By the end of the 1800s, antireligious rationalism manifested itself in various forms of naturalism, positivism, scientism, secularism, and materialism. In a less sophisticated form it still survives as a kind of folklore tradition that (1) reason in an age of science has demolished all forms of spiritual and supernatural reality and knowledge; (2) only rationalism inspires hatred of hypocrisy and teaches moral and intellectual honesty, inspiring courage in the fight for social justice; and (3) only those who deny Christianity, and embrace atheism are true rationalists.

Positive Aspect. Religious or theological rationalism may also refer to the fact that the Jewish, Muslim, and Christian religions, although based on divine revelation, expect reason to perform its natural work of inquiry, consideration, and formulation. This results in a theological expression of revealed truth, an organized effort to understand what one believes, sometimes referred to as rationalistic theology. From the early Apologists of the 3d century, through nicholas oresme to L. E. M. bautain, the Catholic Church has condemned thinkers who unduly minimize reason; similarly, theological systems holding that revelation has been given man as a substitute for all other knowledge have been rejected. The distinction between reason and faith has been steadily maintained, however, and when these are seen in proper relation, the individual believer is free to use understanding and reason in many ways. St. Paul's reference to inexcusable ignorance of the existence of God (Rom 1.20) itself initiated an untiring effort to blend religious faith with rational speculation. Catholic theology, as a consequence, presupposes the truths of natural reason as preambula fidei.

Medieval Thought. For St. Augustine, the perfect kind of rational knowledge was the philosophy of Plato and Plotinus. St. anselm of canterbury regarded logical knowledge as true rational knowledge, but his Credo ut intelligam implied that, with faith as a necessary condition, a deeper understanding of religious truth could be achieved by the application of reason. His ontological argument for the existence of God was rationalistic, however, in the sense that it proceeded independently of natural experience, although within the context of faith and the truths guaranteed by authority.

Pope Pius IX, in the 19th century, defended the scholasticism of the high Middle Ages against the suspicion of rationalism raised by A. bonnetty, maintaining that "the method which St. Thomas and St. Bonaventure and other scholastics after them used does not lead to rationalism " (H. Denzinger, Enchiridion symbolorum, ed. A. Schönmetzer, 2814). Yet the use of Aristotelian dialectic in medieval scholasticism did give birth to a system of purely rational truth out of which modern philosophy was to be born.

Unlike the Jewish philosopher Moses maimonides, the Muslim Averroës stressed that philosophy should be kept apart from theology. He justified a complete separation on the rationalistic principle that what was necessarily and genuinely true in philosophy could contradict the teaching of Christian revelation, in his case, the Qurān (see double truth, theory of). Christian theologians such as siger of brabant promoted a Latin averroism that the condemnations of 1270 and 1277, by Étienne tempier, Bishop of Paris, could not completely eradicate. This influence continued through the Averroistic Aristotelians at Padua to the libertines of the 17th and 18th centuries.

Reformation. Among Protestants, P. melanchthon developed a Christian rationalism designed to meet the age-old need of understanding what was known by faith. In Italy, socinianism exemplified a Protestant rationalist position in theology that was destructive of the revealed doctrine of the Trinity. Similarly, in 18th-century Germany, Protestant theologians accepted a distinction proposed by J. S. Semler between religion (understood more as an ethics) and theology, together with a similar separation of religion from theological opinion and religious usage fostered by J. G. herder. Such distinctions, made originally to safeguard religion from attacks on theology and Biblical history, led eventually to a disavowal of the true supernatural nature of revelation as the word of God. It left reason and its resources supreme and, by the end of the 19th century, led to the very antireligious naturalism that Protestant theological rationalists had sought to prevent.

Meanwhile, F. D. E. schleiermacher maintained that religion consists in neither knowledge nor action, but rather in the consciousness of absolute dependence on God. Thus he replaced the Church by a purely individual commitment and opened the way to a philosophy of power that was fatal to both rationalism and Christianity. These developments provided scriptural exegetes with new critical principles whose application led to extremes of naturalism in such works as the Leben Jesu of D. F. strauss.

Modern Thought. Nineteenth-century Catholic theologians such as G. hermes and A. gÜnther attempted unsuccessfully to relate Catholicism to the pure rationalism of post-Kantian philosophy. But with God, reason, and faith united in the Hegelian system, they could not avoid reducing faith to a work of unaided reason, thereby denying the gratuity of revealed truth. The Danish Lutheran, S. A. kierkegaard, on the other hand, gave attractive expression in his writings to an acceptable position; this regards faith as a personal commitment that neither results from a rationalistic (or historical) mode of argumentation nor is a rational exercise associated with the unfolding of Absolute Mind.

The failure of some contemporary Catholic writers to represent adequately the Catholic view of the relationships between faith and reason and between theology and philosophy has caused reactions against rationalist philosophy to be interpreted as attacks on thomism or on other scholastic syntheses. Some of the literature of existentialism augments this confusion, for its horror of the systematized and the objectivized is basically an aversion from the excesses of rationalism.

Critique. Both philosophical and religious rationalism must be criticized for neglect of evidence. Philosophical rationalism fails to take into account prephilosophical and prescientific knowledge, tending to consider specialized attitudes or techniques as the only rational method. Religious rationalism too often simply makes an act of faith in the all-embracing character of a currently successful method of knowing; it refuses even to consider the data of revelation, and thus cuts itself off completely from the highest source of human knowledge.

See Also: reasoning; kantianism; deism; theism.

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[j. e. gurr]

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