The object of this essay is to consider the character and pedigree of the most remarkable intellectual fashion of post-Renaissance Europe. The Rationalism with which I am concerned is modern Rationalism. No doubt its surface reflects the light of rationalisms of a more distant past, but in its depth there is a quality exclusively its own, and it is this quality that I propose to consider, and to consider mainly in its impact upon European politics. What I call Rationalism in politics is not, of course, the only (and it is certainly not the most fruitful) fashion in modern European political thinking. But it is a strong and a lively manner of thinking which, finding support in its filiation with so much else that is strong in the intellectual composition of contemporary Europe, has come to colour the ideas, not merely of one, but of all political persuasions, and to flow over every party line. By one road or another, by conviction, by its supposed inevitability, by its alleged success, or even quite unreflectively, almost all politics today have become Rationalist or near-Rationalist.
The general character and disposition of the Rationalist are, I think., difficult to identify. At bottom he stands (he always stands) for independence of mind on all occasions, for thought free from obligation to any authority save the authority of reason'. His circumstances in the modern world have made him contentious: he is the enemy of authority, of prejudice, of the merely traditional, customary or habitual. His mental attitude is at once sceptical and optimistic: sceptical, because there is no opinion, no habit, no belief, nothing so firmly rooted or so widely held that he hesitates to question it and to judge it by what he calls his 'reason'; optimistic, because the Rationalist never doubts the power of his 'reason (when properly applied) to determine the worth of a thing, the truth of an opinion or the propriety of an action. Moreover, he is fortified by a belief in a reason' common to all mankind, a common power of rational consideration, which is the ground and inspiration of argument: set up on his door is the precept of Parmenides--judge by rational argument. But besides this, which gives the Rationalist a touch of intellectual equalitarianism, he is something also of an individualist, finding it difficult to believe that anyone who can think honestly and clearly will think differently from himself.
But it is an error to attribute to him an excessive concern with a priori argument. He does not neglect experience, but he often appears to do so because he insists always upon it being his own experience (wanting to begin everything de novo), and because of the rapidity with which he reduces the tangle and variety of experience to a set of principles which he will then attack or defend only upon rational grounds. He has no sense of the cumulation of experience, only of the readiness of experience when it has been converted into a formula: the past is significant to him only as an encumbrance He has none of that negative capability (which Keats attributed to Shakespeare), the power of accepting the mysteries and uncertainties of experience without any irritable search for order and distinctness, only the capability of subjugating experience; he has no aptitude for that close and detailed appreciation of what actually presents itself which Lichtenberg called negative enthusiasm, but only the power of recognizing the large outline which a general theory imposes upon events. His cast of mind is gnostic, and the sagacity of Ruhnken's rule, Oportet quaedam nescire, is lost upon him. There are some minds which give us the sense that they have passed through an elaborate education which was designed to initiate them into the traditions and achievements of their civilization; the immediate impression we have of them is an impression of cultivation, of the enjoyment of an inheritance. But this is not so with the mind of the Rationalist, which impresses us as, at best, a finely tempered, neutral instrument, as a well-trained rather than as an educated mind. Intellectually, his ambition is not so much to share the experience of the race as to be demonstrably a self-made man. And this gives to his intellectual and practical activities an almost preternatural deliberateness and self-consciousness, depriving them of any element of passivity, removing from them all sense of rhythm and continuity and dissolving them into a succession of climacterics, each to be surmounted by a tour de raison. His mind has no atmosphere, no changes of season and temperature; his intellectual processes, so far as possible, are insulated from all external influence and go on in the void. And having cut himself off from the traditional knowledge of his society, and denied the value of any education more extensive than a training in a technique of analysis, he is apt to attribute to mankind a necessary inexperience in all the critical moments of life, and if he were more self-critical he might begin to wonder how the race had ever succeeded in surviving. With an almost poetic fancy, he strives to live each day as if it were his first, and he believes that to form a habit is to fail. And if, with as yet no thought of analysis, we glance below the surface, we may, perhaps, see in the temperament, if not in the character, of the Rationalist, a deep distrust of time, an impatient hunger for eternity and an irritable nervousness in the face of everything topical and transitory.
Now, of all worlds, the world of politics might seem the least amenable to rationalist treatment--politics, always so deeply veined with both the traditional, the circumstantial and the transitory. And, indeed, some convinced Rationalists have admitted defeat here: Clemenceau, intellectually a child of the modern Rationalist tradition (in his treatment of morals and religion, for example), was anything but a Rationalist in politics. But not all have admitted defeat. If we except religion, the greatest apparent victories of Rationalism have been in politics: it is not to be expected that whoever is prepared to carry his rationalism into the conduct of life will hesitate to carry it into the conduct of public affairs. 
But what is important to observe in such a man (for it is characteristic) is not the decisions and actions he is inspired to make, but the source of his inspiration, his idea (and with him it will be a deliberate and conscious idea) of political activity. He believes, of course, in the open mind, the mind free from prejudice and its relic, habit. He believes that the unhindered human 'reason' (if only it can be brought to bear) is an infallible guide in political activity. Further, he believes in argument as the technique and operation of reason'; the truth of an opinion and the 'rational' ground (not the use) of an institution is all that matters to him. Consequently, much of his political activity consists in bringing the social, political, legal and institutional inheritance of his society before the tribunal of his intellect; and the rest is rational administration, 'reason' exercising an uncontrolled jurisdiction over the circumstances of the case. To the Rationalist, nothing is of value merely because it exists (and certainly not because it has existed for many generations), familiarity has no worth, and nothing is to be left standing for want of scrutiny. And his disposition makes both destruction and creation easier for him to understand and engage in, than acceptance or reform. To patch up, to repair (that is, to do anything which requires a patient knowledge of the material), he regards as waste of time: and he always prefers the invention of a new device to making use of a current and well-tried expedient. He does not recognize change unless it is a self-consciously induced change, and consequently he falls easily into the error of identifying the customary and the traditional with the changeless. This is aptly illustrated by the rationalist attitude towards a tradition of ideas. There is, of course, no question either of retaining or improving such a tradition, for both these involve an attitude of submission. It must be destroyed. And to fill its place the Rationalist puts something of his own making--an ideology, the formalized abridgment of the supposed substratum of rational truth contained in the tradition.
The conduct of affairs, for the Rationalist, is a matter of solving problems, and in this no man can hope to be successful whose reason has become inflexible by surrender to habit or is clouded by the fumes of tradition. In this activity the character which the Rationalist claims for himself is the character of the engineer, whose mind (it is supposed) is controlled throughout by the appropriate technique and whose first step is to dismiss from his attention everything not directly related to his specific intentions. This assimilation of politics to engineering is, indeed, what may be called the myth of rationalist politics. And it is, of course, a recurring theme in the literature of Rationalism. The politics it inspires may be called the politics of the felt need; for the Rationalist, politics are always charged with the feeling of the moment. He waits upon circumstance to provide him with his problems, but rejects its aid in their solution. That anything should be allowed to stand between a society and the satisfaction of the felt needs of each moment in its history must appear to the Rationalist a piece of mysticism and nonsense. And his politics are, in fact, the rational solution of those practical conundrums which the recognition of the sovereignty of the felt need perpetually creates in the life of a society. Thus, political life is resolved into a succession of crises, each to be surmounted by the application of reason'. Each generation, indeed, each administration, should see unrolled before it the blank sheet of infinite possibility. And if by chance this tabula rasa has been defaced by the irrational scribblings of tradition-ridden ancestors, then the first task of the Rationalist must be to scrub it clean; as Voltaire remarked, the only way to have good laws is to burn all existing laws and to start afresh. 
Two other general characteristics of rationalist politics may be observed. They are the politics of perfection, and they are the politics of uniformity; either of these characteristics without the other denotes a different style of politics. The essence of rationalism is their combination. The evanescence of imperfection may be said to be the first item of the creed of the Rationalist. He is not devoid of humility; he can imagine a problem which would remain impervious to the onslaught of his own reason. But what he cannot imagine is politics which do not consist in solving problems, or a political problem of which there is no 'rational' solution at all. Such a problem must be counterfeit. And the 'rational' solution of any problem is, in its nature, the perfect solution. There is no place in his scheme for a 'best in the circumstances', only a place for 'the best'; because the function of reason is precisely to surmount circumstances. Of course, the Rationalist is not always a perfectionist in general, his mind governed in each occasion by a comprehensive Utopia; but invariably he is a perfectionist in detail. And from this politics of perfection springs the politics of uniformity; a scheme which does not recognize circumstance can have no place for variety. 'There must in the nature of things be one best form of government which all intellects, sufficiently roused from the slumber of savage ignorance, will be irresistibly incited to approve,' writes Godwin. This intrepid Rationalist states in general what a more modest believer might prefer to assert only in detail; but the principle holds --there may not be one universal remedy for all political ills, but the remedy for any particular ill is as universal in its application as it is rational in its conception. If the rational solution for one of the problems of a society has been determined, to permit any relevant part of the society to escape from the solution is, ex hypothesis, to countenance irrationality. There can be no place for preferences that is not rational preference, and all rational preferences necessarily coincide. Political activity is recognized as the imposition of a uniform condition of perfection upon human conduct.
The modern history of Europe is littered with the projects of the politics of Rationalism. The most sublime of these is, perhaps, that of Robert Owen for 'a world convention to emancipate the human race from ignorance, poverty, division, sin and misery'--so sublime that even a Rationalist (but without much justification) might think it eccentric. But not less characteristic are the diligent search of the present generation for an innocuous power which may safely be made so great as to be able to control all other powers in the human world, and the common disposition to believe that political machinery can take the place of moral and political education. The notion of founding a society, whether of individuals or of States, upon a Declaration of the Rights of Man is a creature of the rationalist brain, so also are 'national' or racial self-determination when elevated into universal principles. The project of the so-called Re-union of the Christian Churches, of open diplomacy, of a single tax, of a civil service whose members 'have no qualifications other than their personal abilities', of a self-consciously planned society, the Beveridge Report, the Education Act of 1944, Federalism, Nationalism, Votes for Women, the Catering Wages Act, the destruction of the Austro-Hungarian Empire, the World State (of H. G. Wells or anyone else), and the revival of Gaelic as the official language of fire, are alike the progeny of Rationalism. The odd generation of rationalism in politics is by sovereign power out of romanticism.
The placid lake of Rationalism lies before us in the character and disposition of the Rationalist, its surface familiar and not unconvincing. its waters fed by many visible tributaries. But in its depths there flows a hidden spring, which, though it was riot the original fountain from which the lake grew, is perhaps the pre-eminent source of its endurance. This spring is a doctrine about human knowledge. That some such fountain lies at the heart of Rationalism will not surprise even those who know only its surface: the superiority of the unencumbered intellect lay precisely in the fact that it could reach more, and more certain, knowledge about man and Society than was otherwise possible: the superiority of the ideology Over the tradition lay in its greater precision and its alleged demonstrability. Nevertheless, it is not, properly speaking, a philosophical theory of knowledge, and it can be explained with agreeable informality.
Every science, every art, every practical activity requiring skill of any sort, indeed every human activity whatsoever, involves knowledge. And, universally, this knowledge is of two sorts, both of which are always involved in any actual activity. It is not, I think, making too much of it to call them two sorts of knowledge, because (though in fact they do not exist separately) there are certain important differences between them. The first sort of knowledge I will call technical knowledge or knowledge of technique. In every art and science, and in every practical activity, a technique is involved. In many activities this technical knowledge is formulated into rules which are, or may be, deliberately learned, remembered, and, as we say, put into practice; but whether or not it is, or has been, precisely formulated, its chief characteristic is that it is susceptible of precise formulation, although special skill and insight may be required to give it that formulation.  The technique (or part of it) of driving a motor car on English roads is to be found in the Highway Code, the technique of cookery is contained in the cookery book, and the technique of discovery in natural science or in history is in their rules of research, of observation and verification. The second sort of knowledge I will call practical, because it exists only in use, is not reflective and (unlike technique) cannot be formulated in rules. This does not mean, however, that it is an esoteric sort of knowledge. It means only that the method by which it may be shared and becomes common knowledge is not the method of formulated doctrine. And if we consider it from this point of view, it would not, I think, be misleading to speak of it as traditional knowledge. In every activity this sort of knowledge is also involved; the mastery of any skill, the pursuit of any concrete activity is impossible without it.
These two sorts of knowledge, then, distinguishable but inseparable, are the twin components of the knowledge involved in every concrete human activity. In a practical art, such as cookery, nobody supposes that the knowledge that belongs to the good cook is confined to what is or may be written down in the cookery book; technique and what I have called practical knowledge combine to make skill in cookery wherever it exists. And the same is true of the fine arts, of painting, of music, of poetry; a high degree of technical knowledge, even where it is both subtle and ready, is one thing; the ability to create a work of art, the ability to compose something with real music qualities, the ability to write a great sonnet, is another, and requires, in addition to technique, this other sort of knowledge. Again, these two sorts of knowledge are involved in any genuinely scientific activity.  The natural scientist will certainly make use of the rules of observation and verification that belong to his technique, but these rules remain only one of the components of his knowledge; advance in scientific discovery was never achieved merely by following the rules.  The same situation may be observed also in religion. It would, I think, be excessively liberal to call a man a Christian who was wholly ignorant of the technical side of Christianity, who knew nothing of creed or formulary, but it would be even more absurd to maintain that even the readiest knowledge of creed and catechism ever constituted the whole of the knowledge that belongs to a Christian. And what is true of cookery, of painting, of natural science and of religion, is no less true of politics: the knowledge involved in political activity is both technical and practica1.  Indeed, as in all arts which have men as their plastic material, arts such as medicine, industrial management, diplomacy, and the art of military command, the knowledge involved in political activity is pre-eminently of this dual character. Nor, in these arts, is it correct to say that whereas technique will tell a man (for example, a doctor) what to do, it is practice which tells him how to do it--the 'bed-side manner', the appreciation of the individual with whom he has to deal.
Even in the what, and above all in diagnosis, there lies already this dualism of technique and practice: there is no knowledge which is not 'know how'. Nor, again, does the distinction between technical and practical knowledge coincide with the distinction between a knowledge of means and a knowledge of ends, though on occasion it may appear to do so. In short, nowhere, and pre-eminently not in political activity, can technical knowledge be separated from practical knowledge, and nowhere can they be considered identical with one another or able to take the place of one another. 
Now, what concerns us are the differences between these two sorts of knowledge; and the important differences are those which manifest themselves in the divergent ways in which these sorts of knowledge can be expressed and in the divergent ways in which they can be learned or acquired.
Technical knowledge, we have seen, is susceptible of formulation in rules, principles, directions, maxims -- comprehensively, in propositions. It is possible to write down technical knowledge in a book. Consequently, it does not surprise us that when an artist writes about his art, he writes only about the technique of his art. This is so, not because he is ignorant of what may be called aesthetic element, or thinks it unimportant, but because what he has to say about that he has said already (if he is a painter) in his pictures, and he knows no other way of saying it. And the same is true when a religious man writes about his religion ; or a cook about cookery.
And it may be observed that this character of being susceptible of precise formulation gives to technical knowledge at least the appearance of certainty: it appears to be possible to be certain about a technique. On the other hand, it is a characteristic of practical knowledge that it is not susceptible of formulation of this kind. Its normal expression is in a customary or traditional way of doing things, or, simply, in practice. And this gives it the appearance of imprecision and consequently of uncertainty, of being a matter of opinion, of probability rather than truth. It is, indeed, a knowledge that is expressed in taste or connoisseurship, lacking rigidity and ready for the impress of the mind of the learner.
Technical knowledge can be learned from a book; it can be learned in a correspondence course. Moreover, much of it can be learned by heart, repeated by rote, and applied mechanically: the logic of the syllogism is a technique of this kind. Technical knowledge, in short, can be both taught and learned in the simplest meanings of these words. On the other hand, practical knowledge can neither be taught nor learned, but only imparted and acquired. It exists only in practice, and the only way to acquire it is by apprenticeship to a master--not because the master can teach it (he cannot), but because it can be acquired only by continuous contact with one who is perpetually practising it. In the arts and in natural science what normally happens is that the pupil, in being taught and in learning the technique from his master, discovers himself to have acquired also another sort of knowledge than merely technical knowledge, without it ever having been precisely imparted and often without being able to say precisely what it is. Thus a pianist acquires artistry as well as technique, a chess-player style and insight into the game as well as a knowledge of the moves, and a scientist acquires (among other things) the sort of judgment which tells him when his technique is leading him astray and the connoisseurship which enables him to distinguish the profitable from the unprofitable directions to explore.
Now, as I understand it, Rationalism is the assertion that what I have called practical knowledge is not knowledge at all, the assertion that, properly speaking, there is no knowledge which is not technical knowledge. The Rationalist holds that the only element of knowledge involved in any human activity is technical knowledge, and that what I have called practical knowledge is really only a sort of nescience which would be negligible if it were not positively mischievous. The sovereignty of reason: for the Rationalist, means the sovereignty of technique.
The heart of the matter is the pre-occupation of the Rationalist with certainty. Technique and certainty are, for him, inseparably joined because certain knowledge is, for him, knowledge which does not require to look beyond itself for its certainty; knowledge, that is, which not only ends with certainty but begins with certainty and is certain throughout. And this is precisely what technical knowledge appears to be. It seems to be a self-complete sort of knowledge because it seems to range between an identifiable initial point (where it breaks in upon sheer ignorance) and an identifiable terminal point, where it is complete, as in learning the rules of a new game. It has the aspect of knowledge that can be contained wholly between the two covers of a book, whose application is, as nearly as possible, purely mechanical, and which does not assume a knowledge not itself provided in the technique. For example, the superiority of an ideology over a tradition of thought lies in its appearance of being self-contained It can be taught best to those whose minds are empty; and if it is to be taught to one who already believes something, the first step of the teacher must be to administer a purge, to make certain that all prejudices and preconceptions are removed, to lay his foundation upon the unshakable rock of absolute ignorance. In short, technical knowledge appears to be the only kind of knowledge which satisfies the standard of certainty which the Rationalist has chosen.
Now, I have suggested that the knowledge involved in every concrete activity is never solely technical knowledge. If this is true, it would appear that the error of the Rationalist is of a simple sort --the error of mistaking a part for the whole, of endowing a part with the qualities of the whole. But the error of the Rationalist does not stop there. If his great illusion is the sovereignty of technique, he is no less deceived by the apparent certainty of technical knowledge. The superiority of technical knowledge lay in its appearance of springing from pure ignorance and ending in certain and complete knowledge, its appearance of both beginning and ending with certainty. But, in fact, this in an illusion. As with every other sort of knowledge, learning a technique does not consist in getting rid of pure ignorance, but in reforming knowledge which is already there. Nothing, not even the most nearly self-contained technique (the rules of a game), can in fact be imparted to an empty mind; and what is imparted is nourished by what is already there. A man who knows the rules of one game will, on this account, rapidly learn the rules of another game; and a man altogether unfamiliar with 'rules' of any kind (if such can be imagined) would be a most unpromising pupil. And just as the self-made man is never literally self-made, but depends upon a certain kind of society and upon a large unrecognized inheritance, so technical knowledge is never, in fact, self-complete, and can be made to appear so only if we forget the hypotheses with which it begins. And if its self-completeness is illusory, the certainty which was attributed to it on account of its self-completeness is also an illusion.
But my object is not to refute Rationalism; its errors are interesting only in so far as they reveal its character. We are considering not merely the truth of a doctrine, but the significance of an intellectual fashion in the history of post-Renaissance Europe. And the questions we must try to answer are: What is the generation of this belief in the sovereignty of technique? Whence springs this supreme confidence in human 'reason' thus interpreted? What is the provenance, the context of this intellectual character? And in what circumstances and with what effect did it come to invade European politics?
The appearance of a new intellectual character is like the appearance of a new architectural style; it emerges almost imperceptibly, under the pressure of a great variety of influences, and it is a misdirection of inquiry to seek its origins. Indeed, there are no origins; all that can be discerned are the slowly mediated changes, the shuffling and reshuffling, the flow and ebb of the tides of inspiration, which issue finally in a shape identifiably new. The ambition of the historian is to escape that gross abridgment of the process which gives the new shape a too early or too late and a too precise definition, and to avoid the false emphasis which springs from being over-impressed by the moment of unmistakable emergence. Yet that moment must have a dominating interest for those whose ambitions are not pitched so high. And I propose to foreshorten my account of the emergence of modern Rationalism, the intellectual character and disposition of the Rationalist, by beginning it at the moment when it shows itself unmistakably, and by considering only one element in the context of its emergence. This moment is the early seventeenth century, and it was connected, inter alia, with the condition of knowledge - knowledge of both the natural and the civilized world - at that time.
The state of European knowledge at the beginning of the seventeenth century was peculiar. Remarkable advances had already been achieved, the tide of inquiry flowed as strongly as at any other period in our history, and the fruitfulness of the presuppositions which inspired this inquiry showed no sign of exhaustion. And yet to intelligent observers it appeared that something of supreme importance was lacking. 'The state of knowledge,' wrote Bacon, 'is not prosperous nor greatly advancing.  And this want of prosperity was not attributable to the survival of a disposition of mind hostile to the sort of inquiry that was on foot: it was observed as a hindrance suffered by minds already fully emancipated from the presuppositions (though not, of course, from some of the details) of Aristotelian science. What appeared to be lacking was not inspiration or even methodical habits of inquiry, but a consciously formulated technique of research, an art of interpretation, a method whose rules had been written down. And the project of making good this want was the occasion of the unmistakable emergence of the new intellectual character I have called the Rationalist.
The dominating figures in the early history of this project are, of course, Bacon and Descartes, and we may find in their writings intimations of what later became the Rationalist character.
Bacon's ambition was to equip the intellect with what appeared to him necessary if certain and demonstrable knowledge of the world in which we live is to be attained. Such knowledge is not possible for 'natural reason', which is capable of only 'petty and probable conjectures', not of certainty.  And this imperfection is reflected in the want of prosperity of the state of knowledge. The Novum Organum begins with a diagnosis of the intellectual situation. What is lacking is a clear perception of the nature of certainty and an adequate means of achieving it. 'There remains,' says Bacon, 'but one course for the recovery of a sound and healthy condition-namely, that the entire work of understanding be commenced afresh, and the mind itself be from the very outset not left to take its own course, but guided at every step.  What is required is a 'sure plan', a new 'way'' of understanding, an 'art' or 'method' of inquiry, an 'instrument' which (like the mechanical aids men use to increase the effectiveness of their natural strength) shall supplement the weakness of the natural reason: in short, what is required is a formulated technique of inquiry.  He recognizes that this technique will appear as a kind of hindrance to the natural reason, not supplying it with wings but hanging weights upon it in order to control its exuberance; but it will be a hindrance of hindrances to certainty, because it is lack of discipline which stands between the natural reason and certain knowledge of the world. And Bacon compares this technique of research with the technique of the syllogism, the one being appropriate to the discovery of the truth of things while the other is appropriate only to the discovery of the truth of opinions. 
The art of research which Bacon recommends has three main characteristics. First, it is a set of rules; it is a true technique in that it can be formulated as a precise set of directions which can be learned by heart.  Secondly, it is a set of rules whose application is purely mechanical; it is a true technique because it does not require for its use any knowledge or intelligence not given in the technique itself. Bacon is explicit on this point. The business of interpreting nature is 'to be done as if by machinery',  'the strength and excellence of the wit (of the inquirer) has little to do with the matter', the new method 'places all wits and understandings nearly on a level'.  Thirdly, it is a set of rules of universal application; it is a true technique in that it is an instrument of inquiry indifferent to the subject-matter of the inquiry.
Now, what is significant in this project is not the precise character of the rules of inquiry, both positive and negative, but the notion that a technique of this sort is even possible. For what is proposed--infallible rules of discovery--is something very remarkable, a sort of philosopher's stone, a key to open all doors, a 'master science'. Bacon is humble enough about the details of this method, he does not think he has given it a final formulation; but his belief in the possibility of such a 'method' in general is unbounded.  From our point of view, the first of his rules is the most important, the precept that we must lay aside received opinion, that we must 'begin anew from the very foundations'.  Genuine knowledge must begin with a purge of the mind, because it must begin as well as end in certainty and must be complete in itself. Knowledge and opinion are separated absolutely: there is no question of ever winning true knowledge out of 'the childish notions we at first imbibed'. And this, it may be remarked, is what distinguishes both Platonic and Scholastic from modern Rationalism: Plate is a rationalist, but the dialectic is not a technique, and the method of Scholasticism always had before it a limited aim.
The doctrine of the Novum Organum may be summed up, from our point of view, as the sovereignty of technique. It represents, not merely a preoccupation with technique combined with a recognition that technical knowledge is never the whole of knowledge, but the assertion that technique and some material for it to work upon are all that matters. Nevertheless, this is not itself the beginning of the new intellectual fashion, it is only an early and unmistakable intimation of it: the fashion itself may be said to have sprung from the exaggeration of Bacon's hopes rather than from the character of his beliefs.
Descartes, like Bacon, derived inspiration from what appeared to be the defects of contemporary inquiry; he also perceived the lack of a consciously and precisely formulated technique of inquiry. And the method propounded in the Discours de la Methode and the Regulae corresponds closely to that of the Novum Organum. For Descartes, no less than for Bacon, the aim is certainty. Certain knowledge can spring up only in an emptied mind; the technique of research begins with an intellectual purge. The first principle of Descartes is 'de ne recevoir jamais aucune chose pour vraie que je ne la connusse evidemment etre telle, c'est-a-dire d'eviter soigneusement la precipitation et la prevention','de batir dans un fonds qui est tout a moi'; and the inquirer is said to be 'comme un homme qui marche seul et dans les tenebres'.  Further, the technique of inquiry is formulated in a set of rules which, ideally, compose an infallible method whose application is mechanical and universal. And thirdly, there are no grades in knowledge, what is not certain is mere nescience. Descartes, however, is distinguished from Bacon in respect of the thoroughness of his education in the Scholastic philosophy and in the profound impression that geometrical demonstration had upon his mind, and the effect of these differences in education and inspiration is to make his formulation of the technique of inquiry more precise and in consequence more critical.
His mind is oriented towards the project of an infallible and universal method or research, but since the method he propounds is modelled on that of geometry, its limitation when applied, not to possibilities but to things, is easily apparent. Descartes is more thorough than Bacon in doing his scepticism for himself and, in the end, he recognizes it to be an error to suppose that the method can ever be the sole means of inquiry.  The sovereignty of technique turns out to be a dream and not a reality. Nevertheless, the lesson his successors believed themselves to have learned from Descartes was the sovereignty of technique and not his doubtfulness about the possibility of an infallible method.
By a pardonable abridgment of history, the Rationalist character may be seen springing from the exaggeration of Bacon's hopes and the neglect of the scepticism of Descartes; modern Rationalism is what commonplace minds made out of the inspiration of men of discrimination and genius. Les grands hommes, en apprenant auxfaibles a reflechir, les ont mis sur la route de I'erreur. But the history of Rationalism is not only the history of the gradual emergence and definition of this new intellectual character; it is, also, the history of the invasion of every department of intellectual activity by the doctrine of the sovereignty of technique. Descartes never became a Cartesian; but, as Bouillier says of the seventeenth century, 'le cartesianisme a triomphe; il s'est empare du grand siecle tout entier, il a penetre de son esprit, non seulement la philosophie, mais les sciences et les lettres ellesmemes'.  It is common knowledge that, at this time, in poetry and in drama, there was a remarkable concentration on technique, on rules of composition, on the observance of the bienseances of literature, which continued unabated for nearly two centuries. A stream of books flowed from the presses on the 'art of poetry', the 'art of living', the 'art of thinking'. Neither religion, nor natural science, nor education, nor the conduct of life itself escaped from the influence of the new Rationalism; no activity was immune, no society untouched. 
The slowly mediated changes by which the Rationalist of the seventeenth century became the Rationalist as we know him today, are a long and complicated story which I do not propose even to abridge. It is important only to observe that, with every step it has taken away from the true sources of its inspiration, the Rationalist character has become cruder and more vulgar. What in the seventeenth century was 'L'art de penser' has now become Your mind and how to use it, a plan by world-famous experts for developing a trained mind at a fraction of the usual cost. What was the Art of Living has become the Technique of Success, and the early and more modest incursions of the sovereignty of technique into education have blossomed into Pelmanism.
The deeper motivations which encouraged and developed this intellectual fashion are, not unnaturally, obscure; they are hidden in the recesses of European society. But among its other connections, it is certainly closely allied with a decline in the belief in Providence: a beneficient and infallible technique replaced a beneficient and infallible God; and where Providence was not available to correct the mistakes of men it was all the more necessary to prevent such mistakes. Certainly, also, its provenance is a society or a generation which thinks what it has discovered for itself is more important than what it has inherited,  an age over-impressed with its own accomplishment and liable to those illusions of intellectual grandeur which are the characteristic lunacy of post-Renaissance Europe, an age never mentally at peace with itself because never reconciled with its past. And the vision of a technique which puts all minds on the same level provided just the short-cut which would attract men in a hurry to appear educated but incapable of appreciating the concrete detail of their total inheritance.
And, partly under the influence of Rationalism itself, the number of such men has been steadily growing since the seventeenth century.  Indeed it may be said that all, or almost all, the influences which in its early days served to encourage the emergence of the Rationalist character have subsequently become more influential in our civilization.
Now, it is not to be thought that Rationalism established itself easily and without opposition. It was suspect as a novelty, and some fields of human activity-literature, for example -- on which at first its hold was strong, subsequently freed themselves from its grasp. Indeed, at all levels and in all fields there has been continuous criticism of the resistance to the teachings of Rationalism. And the significance of the doctrine of the sovereignty of technique becomes clearer when we consider what one of its first and profoundest critics has to say about it. Pascal is a judicious critic of Descartes, not opposing him at all points, but opposing him nevertheless, on points that are fundamental.  He perceived, first, that the Cartesian desire for certain knowledge was based upon a false criterion of certainty. Descartes must begin with something so sure that it cannot be doubted, and was led, as a consequence, to believe that all genuine knowledge is technical knowledge.
Pascal avoided this conclusion by his doctrine of probability: the only knowledge that is certain is certain on account of its partiality; the paradox that probable knowledge has more of the whole truth than certain knowledge Secondly, Pascal perceived that the Cartesian raisonnement is never in fact the whole source of the knowledge involved in any concrete activity. The human mind, he asserts, is not wholly dependent for its successful working upon a conscious and formulated technique; and even where a technique is involved, the mind observes the technique 'tacitement, naturellement et sans art'. The precise formulation of rules of inquiry endangers the success of the inquiry by exaggerating the importance of method. Pascal was followed by others, and indeed much of the history of modern philosophy revolves round this question. But, though later writers were often more elaborate in their criticism, few detected more surely than Pascal that the significance of Rationalism is not its recognition of technical knowledge, but its failure to recognize any other: its philosophical error lies in the certainty it attributes to technique and in its doctrine of the sovereignty of technique; its practical error lies in its belief that nothing but benefit can come from making conduct self-conscious.
[Notes appear the end of "Rationalism in Politics (parts 4 - 5)", published elsewhere in this collection]