Rationalism is both impersonal and non-historical in character. In its Greek form, rationalism posited a god as the First Cause because its thinking was hostile to an infinite regress of causes, and hence a god as the first cause was required. Beyond that, he had little function. As the First Cause, this god was the ultimate idea in that he made unnecessary a blind regression from one cause to another in search of an ever-elusive beginning. This god was impersonal; he was simply a logical necessity as a First Cause, not an object of worship nor investigation, but a limiting concept.
In the development of philosophical thought, the idea of an eternal regress lost its threat to reason. One development in the modern era was the insistence by some pragmatic naturalists that, even as Christianity takes God as its given, so naturalism takes the universe as its given. One such professor stated that arguing against creationism was a mistake: one should simply say, "Even as God is your given, the universe is mine." The reaction to his position was not favorable: the students wanted certainty for their view, which science seemingly offered.
Rationalism offers certainty if its basic premise is accepted, namely, that all things are understandable and penetrable by reason. But basic to Christianity is the premise of the incomprehensibility of God. He is far beyond man’s comprehension and he can only be known by revelation. For the mind of man to comprehend God’s eternity, infinity, omniscience, omnipotence, and being is impossible. God can be known only by his self-revelation, and then he can be known truly but not exhaustively. This was made clear to Moses by the burning bush. Moses, troubled by God’s age-long silence during Israel’s Egyptian sojourn, asked, "What is your Name?" Names were then definitions, and Moses asked God to define himself so that he might be comprehensible. This God refused to do. He simply said, Tell them, the people of Israel, "I AM hath sent me unto you" (Ex 3:14). I am He Who Is, the Eternal One. However, I can be known by my self-revelation, for I am "the LORD God of your fathers, the God of Abraham, the God of Isaac, and the God of Jacob" (Ex 3:15). God reveals himself: he is not discovered by reason because reason poses as an independent faculty in rationalism and as the definer, not the receiver, of truth.
John Calvin stressed the primacy of God’s self-revelation and man’s assent to it, and this gave to consistent Calvinists an unrivaled strength. Francis William Buckler observed that in the Reformation era, "Calvinist renegades were rare" (Francis William Bucker, "An Anthropological Approach to the Origins of Protestantism," in Vergiluis Ferm, editor, The Protestant Credo, p. 152. New York, NY: Philosophical Library, 1953). To stand on the sovereignty of God and of his revelation is to stand on more than one’s rationalizations.
Rationalization always misdefines man. For Aristotle, man was a political animal. For Epictetus, in line with this, man is a member of a city, a polis: still a political animal. All non-Biblical definitions of God reduce man to a creature of natural forces, to another kind of animal, to cite Aristotle. Only in his reason does he to some degree rise above himself. It was thus logical to conclude that people, the political animals, should be ruled by philosopher kings, men whose rationalism had put them in touch with the ultimate (and abstract) ideas. Other men were as cattle and sheep, to be herded into the way they should go.
According to God’s revelation, man is created in God’s image, with his communicable attributes, knowledge, righteousness, and holiness, with dominion over the creatures (Gen. 1:26-28; Col. 3:10; Eph. 4:24). In the Platonic tradition, reason is a tool for domination, to be used by the philosopher-kings to control mankind. In the Christian Faith, the great sacrament of the Lord’s table is accompanied by a collection for charity.
Rationalism sees itself as a liberating force in history when in fact it has been a force for tyranny. Plato’s followers became the tyrants of Greece, and, with the Renaissance, art and tyranny, both neo-Platonic, flourished and brought evils in their wake.