Study of how the existence of evil can be reconciled with God's known attributes; more generally, the study of how we can have knowlege of God
Theodicy.—Etymologically considered theodicy (theos dikē) signifies the justification of God. The term was introduced into philosophy by Leibniz (q.v.), who, in 1710, published a work entitled: "Essais de Theodicee sur la bonte de Dieu, la liberte de l'homme et l'origine du mal". The purpose of the essay was to show that the evil in the world does not conflict with the goodness of God, that, indeed, notwithstanding its many evils, the world is the best of all possible worlds (see Optimism). The problem of evil (see Evil) has from earliest times engrossed the attention of philosophers. The well-known sceptic Pierre Bayle had denied in his "Dictionnaire historique et critique" the goodness and omnipotence of God on account of the sufferings experienced in this earthly life. The "Theodicee" of Leibniz was directed mainly against Bayle. Imitating the example of Leibniz other philosophers now called their treatises on the problem of evil "theodicies". As in a thorough treatment of the question the proofs both of the existence and of the attributes of God cannot be disregarded, our entire knowledge of God was gradually brought within the domain of theodicy. Thus theodicy came to be synonymous with natural theology (theologia naturalis), that is, the department of metaphysics which presents the positive proofs for the existence and attributes of God and solves the opposing difficulties. Theodicy, therefore, may be defined as the science which treats of God through the exercise of reason alone. It is a science because it systematically arranges the content of our knowledge about God and demonstrates, in the strict sense of the word, each of its propositions. But it appeals to nature as its only source of proof, whereas theology sets forth our knowledge of God as drawn from the sources of supernatural revelation.
The first and most important task of theodicy is to prove the existence of God. It is of course presupposed that the suprasensible can be known and that the limits of experience pure and immediate can be transcended. The justification of this assumption must be furnished by other branches of philosophy, e.g. criteriology and general metaphysics. The natural demonstrability of God's existence was always accepted by the majority of theists. Hume and Kant were the first to awaken in the minds of would-be theists serious doubt on this point. Not that these philosophers presented any solid reason against the long-tested arguments for the existence of God, but because in their systems a scientific proof of the existence of a supernatural being is impossible. New ways of establishing theism were now sought. The Scotch School led by Thomas Reid taught that the fact of the existence of God is accepted by us without knowledge of reasons but simply by a natural impulse. That God exists, this school said, is one of the chief metaphysical principles that we accept not because they are evident in themselves or because they can be proved, but because common sense obliges us to accept them. In Germany the School of Jacobi taught that our reason is able to perceive the suprasensible. Jacobi distinguished three faculties: sense, reason, and understanding. Just as sense has immediate perception of the material so has reason immediate perception of the immaterial, while the understanding brings these perceptions to our consciousness and unites them to one another (Stockl, "Geschichte der neueren Philosophic", II, 82 sqq.). God's existence, then, cannot be proved—Jacobi, like Kant, rejected the absolute value of the principle of causality—it must be felt by the mind. In his "Emile", Jean-Jacques Rousseau asserted that when our understanding ponders over the existence of God it encounters nothing but contradictions; the impulses of our hearts, however, are of more value than the understanding, and these proclaim clearly to us the truths of natural religion, e.g., the existence of God, the immortality of the soul, etc. The same. theory was advocated in Germany by Friedrich Schleiermacher (d. 1834), who assumed an inner religious sense by means of which we feel religious truths. According to Schleiermacher, religion consists solely in this inner perception, dogmatic doctrines are unessential (Stockl, loc. cit., 199 sqq.). Nearly all Protestant theologians who have not yet sunken into atheism follow in Schleiermacher's footsteps. They generally teach that the existence of God cannot be demonstrated; certainty as to this truth is only furnished us by inner experience, feeling, and perception.
As is well known the Modernists also deny the demonstrability of the existence of God. According to them we can only know something of God by means of the vital immanence, that is, under favorable circumstances the need of the Divine dormant in our subconsciousness becomes conscious and arouses that religious feeling or experience in which God reveals himself to us (see Modernism). In condemnation of this view the oath against Modernism formulated by Pius X says: "Deum ... naturali rationis lumine per ea quae facta sunt, hoc est per visibilia creationis opera, tanquam causam per effectus certo cognosci adeoque demonstrari etiam posse, profiteor", i.e., I declare that by the natural light of reason, God can be certainly known and therefore His existence demonstrated through the things that are made, i.e., through the visible works of creation, as the cause is known through its effects.
There is, however, still another class of philosophers who assert that the proofs for the existence of God present indeed a fairly large probability but no absolute certainty. A number of obscure points, they say, always remain. In order to overcome these difficulties there is necessary either an act of the will, a religious experience, or the discernment of the misery of the world without God, so that finally the heart makes the decision. This view is maintained, among others, by the noted English statesman Arthur Balfour in his widely read book "The Foundations of Belief" (1895). The opinions set forth in this work were adopted in France by Brunetiere, the editor of the "Revue des deux Mondes". Many orthodox Protestants express themselves in the same manner, as, for instance, Dr. E. Dennert, President of the Kepler Society, in his work "Ist Gott tot?" (Stuttgart, 1908). It must undoubtedly be conceded that for the perception of religious truths the mental attitude and temper are of great importance. As the questions here under consideration are those that penetrate deeply into practical life and their solution is not directly evident, the will is thus able to hold fast to the opposing difficulties and to prevent the understanding from attaining to quiet, objective reflection. But it is false to say that the understanding cannot eliminate every reasonable doubt as to the existence of God, or that a subjective inclination of the heart is a guarantee of the truth, even though there is no evidence that it is based on objective facts. This latter view would open the door wide to religious extravagance. It is not, therefore, an excess of intellectualism to demand that the truths which serve as the rational basis of faith shall be strictly proved.
Even in earlier times there were those who denied that the existence of God could be proved absolutely by the understanding alone, and took refuge in Revelation. In his "Summa contra Gentiles" (I, c. xii) St. Thomas refers to such reasoners. At a later date this opinion was championed by the Nominalists, William of Occam and Gabriel Biel, as well as by the Reformers; the Jansenists demanded the special aid of grace. In the nineteenth century the Traditionalists (see Traditionalism) asserted that only when some vestiges of the original revelation reached man could he deduce with certainty the existence of God. Dr. J. Kuhn, formerly professor at Tubingen, declares that the clear recognition of the existence of God requires a pure soul unstained by sin. Ontologism (q.v.) went to the other extreme and asserted the immediate cognition of God. St. Anselm offered an a priori proof of the existence of God. This, however, has been always and rightly rejected by the majority of Catholic philosophers, notwithstanding the modifications by which Duns Scotus, Leibniz, and Descartes sought to save it (cf. Dr. Otto Paschen, "Der ontologische Gottesbeweis in der Scholastik", Aachen, 1903; M. Esser, "Der ontologische Gottesbeweis und seine Geschichte", Bonn, 1905). In regard to the various a posteriori proofs for the existence of God, see the article God. A dispute has arisen of late as to whether there are a number of proofs of the existence of God or whether all are not merely parts of one and the same proof (cf. Dr. C. Braig, "Gottesbeweis oder Gottesbeweise?", Stuttgart, 1888). It is certain that we always reach God as the cause, the last ground of all existence, and thus constantly follow as a guide the principle of sufficient reason. But the starting-point of the individual proofs varies. St. Thomas calls them aptly (Summ. theol., I, Q. ii, a. 3) vice, i.e., roads to the apprehension of God which all open on the same highway.
After demonstrating the existence of God, theodicy investigates the question as to His nature and attributes. The latter are in part absolute (quiescentia) in part relative (operativa). In the first class belong the infinity, unity, immutability, omnipresence, and eternity; to the second class the knowledge, volition, and action of God. The action of God includes the creation, maintenance, and government of the world, the cooperation of God with the activity of the creature, and the working of miracles. The understanding affords us abundant knowledge concerning God, although it allows us but faint glimpses of His essential greatness and beauty. For one thing should not be forgotten, namely, that all our cognition of God is incomplete and analogous, that is, is formed from notions that we have deduced from created things. Hence it is that much remains obscure to us, as for instance, how God's immutability harmonizes with His freedom, and how He knows the future. But the inadequacy of our knowledge does not justify the assertion of the Agnostic that God is unknowable and that consequently any attempt such as theodicy makes to reason about His attributes and our relations to Him is foredoomed to failure (see Agnosticism).