Quotes From "Critique Of Pure Reason" By Immanuel Kant

Thoughts without content are empty, intuitions without concepts are blind.
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Thoughts without content are empty, intuitions without concepts are blind. Immanuel Kant
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Skepticism is thus a resting-place for human reason, where it can reflect upon its dogmatic wanderings and make survey of the region in which it finds itself, so that for the future it may be able to choose its path with more certainty. But it is no dwelling-place for permanent settlement. Such can be obtained only through perfect certainty in our knowledge, alike of the objects themselves and of the limits within which all our knowledge of objects is enclosed. Immanuel Kant
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It will be seen how there can be the idea of a special science, the *critique of pure reason* as it may be called. For reason is the faculty which supplies the *principles* of *a priori* knowledge. Pure reason therefore is that which contains the principles of knowing something entirely *a priori*. An *organon* of pure reason would be the sum total of the principles by which all pure *a priori* knowledge can be acquired and actually established. Exhaustive application of such an organon would give us a system of pure reason. But as this would be a difficult task, and as at present it is still doubtful whether indeed an expansion of our knowledge is possible here at all, we may regard a science that merely judges pure reason, its sources and limits, as the *propaedeutic* to the system of pure reason. In general, it would have to be called only a *critique*, not a *doctrine* of pure reason. Its utility, in regard to speculation, would only be negative, for it would serve only to purge rather than to expand our reason, and, which after all is a considerable gain, would guard reason against errors. I call all knowledge *transcendental* which deals not so much with objects as with our manner of knowing objects insofar as this manner is to be possible *a priori*. A system of such concepts would be called *transcendental philosophy*. But this is still, as a beginning, too great an undertaking. For since such a science must contain completely both analytic and synthetic *a priori* knowledge, it is, as far as our present purpose is concerned, much too comprehensive. We will be satisfied to carry the analysis only so far as is indispensably necessary in order to understand in their whole range the principles of *a priori* synthesis, with which alone we are concerned. This investigation, which properly speaking should be called only a transcendental critique but not a doctrine, is all we are dealing with at present. It is not meant to expand our knowledge but only to correct it, and to become the touchstone of the value, or lack of value, of all *a priori* knowledge. Such a critique is therefore the preparation, as far as possible, for a new organon, or, if this should turn out not to be possible, for a canon at least, according to which, thereafter, the complete system of a philosophy of pure reason, whether it serve as an expansion or merely as a limitation of its knowledge, may be carried out both analytically and synthetically. That such a system is possible, indeed that it need not be so comprehensive as to cut us off from the hope of completing it, may already be gathered from the fact that it would have to deal not with the nature of things, which is inexhaustible, but with the understanding which makes judgments about the nature of things, and with this understanding again only as far as its *a priori* knowledge is concerned. The supply of this *a priori* knowledge cannot be hidden from us, as we need not look for it outside the understanding, and we may suppose this supply to prove sufficiently small for us to record completely, judge as to its value or lack of value and appraise correctly. Still less ought we to expect here a critique of books and systems of pure reason, but only the critique of the faculty of pure reason itself. Only once we are in possession of this critique do we have a reliable touchstone for estimating the philosophical value of old and new works on this subject. Otherwise, an unqualified historian and judge does nothing but pass judgments upon the groundless assertions of others by means of his own, which are equally groundless. Immanuel Kant
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Our knowledge springs from two fundamental sources of our mind; the first is to receive representations (receptivity of impressions), the second is the faculty of knowing an object through these representations (spontaneity of concepts). Through the first an object is *given* to us, through the second the object is *thought* in relation to that representation (which is a mere determination of the mind). Intuition and concepts constitute, therefore, the elements of all our knowledge, so that neither concepts without an intuition in some way corresponding to them, nor intuition without concepts can yield knowledge. Both are either pure or empirical. They are empirical when they contain sensation (sensation presupposes the actual presence of the object). They are *pure* when no sensation is mixed in with the representation. Sensation may be called the matter of sensible knowledge. Pure intuition, therefore, contains only the form under which something is intuited, and the pure concepts contains only the form of thinking an object in general. Pure intuitions and pure concepts alone are possible *a priori*, empirical intuitions and empirical concepts only *a posteriori*. We call *sensibility* the *receptivity* of our mind to receive representations insofar as it is in some wise affected, while the *understanding*, on the other hand, is our faculty of producing representations by ourselves, or the *spontaneity* of knowledge. We are so constituted that our intuition can never be other than *sensible*; that is, it contains only the mode in which we are affected by objects. The faculty, on the contrary, which enables us to *think* the object of sensible intuition is the *understanding*. Neither of these properties is to be preferred to the other. Without sensibility no object would be given to us, without understanding no object would be thought. Thoughts without content are empty, intuitions without concepts are blind. It is, therefore, just as necessary to make our concepts sensible (i.e., to add the object to them in intuition) as to make our intuitions understandable (i.e., to bring them under concepts). These two faculties or capacities cannot exchange their functions. The understanding cannot intuit anything, the senses cannot think anything. Only from their union can knowledge arise. But this is no reason for confounding their respective contributions; rather, it gives us a strong reason for carefully separating and distinguishing the one from the other. We therefore distinguish the science of the rules of sensibility in general, i.e., aesthetic, from the science of the rules of the understanding in general, i.e., logic."― Transcendental Doctrine of Elements. Transcendental Logic: The Idea of a Transcendental Logic. Immanuel Kant
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To know what questions may reasonably be asked is already a great and necessary proof of sagacity and insight. For if a question is absurd in itself and calls for unnecessary answers, it not only brings disgrace to the person raising it, but may prompt an incautious listener to give absurd answers, thus presenting, as the ancients said, the laughable spectacle of one person milking a he-goat, and another holding the sieve underneath. Immanuel Kant
I had to deny knowledge in order to make room...
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I had to deny knowledge in order to make room for faith. Immanuel Kant
All our knowledge begins with the senses, proceeds then to...
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All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason. Immanuel Kant
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That all our knowledge begins with experience there can be no doubt. For how should the faculty of knowledge be called into activity, if not by objects which affect our senses and which, on the one hand, produce representations by themselves or on the other, rouse the activity of our understanding to compare, connect, or separate them and thus to convert the raw material of our sensible impressions into knowledge of objects, which we call experience? With respect to time, therefore, no knowledge within us is antecedent to experience, but all knowledge begins with it. But though all our knowledge begins with experience, is does not follow that it all arises from experience. For it is quite possible that even our empirical knowledge is a compound of that which we perceive through impressions, and of that which our own faculty of knowledge (incited by sense impressions) supplies from itself, a supplement which we do not distinguish from that raw material until long practice and rendered us capable of separating one from the other. It is therefore a question which deserves at least closer investigation and cannot be disposed of at first sight: Whether there is any knowledge independent of all experience and even of all impressions of the senses? Such knowledge is called 'a priori' and is distinguished from empirical knowledge, which has its source 'a posteriori', that is, in experience.. Immanuel Kant
Philosophical knowledge is knowledge which reason gains from concepts mathematical...
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Philosophical knowledge is knowledge which reason gains from concepts mathematical knowledge is knowledge which reason gains from the construction of concepts. Immanuel Kant
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(On the seeming futility of metaphysics) Why then has nature afflicted our reason with the restless striving for such a path, as if it were one of reason's most important occupations? Still more, how little cause have we to place trust in our reason if in one of the most important parts of our desire for knowledge it does not merely forsake us but even entices us with delusions and in the end betrays us! Or if the path has merely eluded us so far, what indications may we use that might lead us to hope that in renewed attempts we will be luckier than those who have gone before us? . Immanuel Kant
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[At the beginning of modern science], a light dawned on all those who study nature. They comprehended that reason has insight only into what it itself produces according to its own design; that it must take the lead with principles for its judgments according to constant laws and compel nature to answer its questions, rather than letting nature guide its movements by keeping reason, as it were, in leading-strings; for otherwise accidental observations, made according to no previously designed plan, can never connect up into a necessary law, which is yet what reason seeks and requires. Reason, in order to be taught by nature, must approach nature with its principles in one hand, according to which alone the agreement among appearances can count as laws, and, in the other hand, the experiments thought in accordance with these principles - yet in order to be instructed by nature not like a pupil, who has recited to him whatever the teacher wants to say, but like an appointed judge who compels witnesses to answer the questions he puts to them. Thus even physics owes the advantageous revolution in its way of thinking to the inspiration that what reason would not be able to know of itself and has to learn from nature, it has to seek in the latter (though not merely ascribe to it) in accordance with what reason itself puts into nature. This is how natural science was first brought to the secure course of a science after groping about for so many centuries. Immanuel Kant
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Whereas the beautiful is limited, the sublime is limitless, so that the mind in the presence of the sublime, attempting to imagine what it cannot, has pain in the failure but pleasure in contemplating the immensity of the attempt Immanuel Kant
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Metaphysics.. is nothing but the inventory of all we possess through pure reason, ordered systematically. Nothing here can escape us, because what reason brings forth entirely out of itself cannot be hidden, but is brought to light by reason itself as soon as reason's common principle has been discovered. The perfect unity of this kind of cognition, and the fact that it arises solely out of pure concepts without any influence that would extend or increase it from experience or even particular intuition, which would lead to a determinate experience, make this unconditioned completeness not only feasible but also necessary. Tecum habita, et noris quam sit tibi curta supellex. Dwell in your own house, and you will know how simple your possessions are. - Persius. Immanuel Kant
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...Reason should take on anew the most difficult of all its tasks, namely, that of self-knowledge, and to institute a court of justice, by which reason may secure its rightful claims while dismissing all its groundless pretensions, and this not by mere decrees but according to its own eternal and unchangeable laws; and this court is none other than the critique of pure reason itself. Immanuel Kant
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Enlightenment is man's emergence from his self-imposed immaturity. Nothing is required for this enlightenment except freedom; and the freedom in question is the least harmful of all, namely, the freedom to use with and publicly in all matters. Immanuel Kant