When it turned its gaze to History, Rationalism saw the whole tendency as one toward Reason. Man was "emerging" during all those millennia, he was progressing from barbarism and fanaticism to enlightenment, from "superstition" to "science," from violence to "reason," from dogma to "criticism, from darkness to light. No more invisible things, no more spirit, no more soul, no more God, no more Church and State. The two poles of thought are "the individual" and "humanity." Anything separating them is "irrational."

This branding of things as irrational is in fact correct. Rationalism must mechanize everything, and whatever cannot be mechanized is of necessity irrational. Thus the entirety of History becomes irrational: its chronicles, its processes, its secret force, Destiny. Rationalism itself, as a by-product of a certain stage in the development of a High Culture, is also irrational.

The "Enlightenment" period of Western history which ... set in after the Counter-Reformation laid more and more stress on intellect, reason and logic as it developed. By the middle of the 18th century this tendency produced Rationalism. Rationalism regarded all spiritual values as its objects and proceeded to revalue them from the standpoint of "reason." Inorganic logic is the faculty men have always used for solving problems of mathematics, engineering, transportation, physics and in other non-valuing situations. Its insistence on identity and rejection of contradiction are practicable in material activity. They afford intellectual satisfaction also in matters of purely abstract thought, like mathematics and logic, but if pursued far enough they turn into mere techniques, simple assumptions whose only justification is empirical. The end of Rationalism is Pragmatism, the suicide of Reason.

This adaptation of reason to material problems causes all problems whatever to become mechanical when surveyed in "the light of reason," without any mystical admixture of thought or tendency whatever. Descartes reasoned the animals into automata, and a generation or so later, man himself was rationalized into an automaton — or equally, an animal. Organisms became problems in chemistry and physics, and superpersonal organism[s] simply no longer existed, for they are not amenable to reason, not being visible or measurable. Newton provided the universe of stars with a non-spiritual self-regulating force; the next century removed the spirit from man, his history and his affairs.

Reason detests the inexplicable, the mysterious, the half-light. In a practical problem in machinery or ship-building one must feel that all the factors are under his knowledge and control. There must be nothing unpredictable or out of control. Rationalism, which is the feeling that everything is subject to and completely explicable by Reason, consequently rejects everything not visible and calculable. If a thing actually cannot be calculated, Reason merely says that the factors are so numerous and complicated that in a purely practical way they render the calculation unfeasible, but do not make it theoretically impossible. Thus Reason also has its Will-to-Power: whatever does not submit is pronounced recalcitrant, or is simply denied existence.