critique of pure reason

Immanuel Kant

is a particular science whereby reason is the faculty which furnishes us with the principles of knowledge a priori -- hence, pure reason is the faculty which contains the principles of cognizing anything absolutely a priori.

From all that has been said, there results the idea of a particular science, which may be called the Critique of Pure Reason. For reason is the faculty which furnishes us with the principles of knowledge a priori. Hence, pure reason is the faculty which contains the principles of cognizing anything absolutely a priori. (KANT CPR 33)

is a science of the mere criticism of pure reason, its sources and limits -as the introduction to a system of pure reason.

As this, however, is demanding a great deal, and it is yet doubtful whether any extension of our knowledge be here possible, or, if so, in what cases... we can regard a science of the mere criticism of pure reason, its sources and limits, as the propaedeutic to a system of pure reason. Such a science must not be called a doctrine, but only a critique of pure reason... (33)

is concerned not with the nature of outward objects, which is infinite, but solely with the mind, which judges of the nature of objects, and, again, with the mind only in respect of its cognition a priori -it is a search within ourselves, not without -and limited enough to survey the whole thing.

For we have not here to do with the nature of outward objects, which is infinite, but solely with the mind, which judges of the nature of objects, and, again, with the mind only in respect of its cognition a priori. And the object of our investigations, as it is not to be sought without, but, altogether within, ourselves, cannot remain concealed, and in all probability is limited enough to be completely surveyed and fairly estimated, according to its worth or worthlessness. Still less let the reader here expect a critique of books and systems of pure reason... our present object is exclusively a critique of the faculty of pure reason itself. Only when we make this critique our foundation, do we possess a pure touchstone for estimating the philosophical value of ancient and modern writings on this subject... and without this criterion, the incompetent historian or judge decides upon and corrects the groundless assertions of others with his own, which have themselves just as little foundation. (CPR : 34)

is, in regard to speculation, only negative in use. It aims not to enlarge the bounds of, but to purify, our reason, and to shield against error -which alone is no little gain.

and its use, in regard to speculation, would be only negative, not to enlarge the bounds of, but to purify, our reason, and to shield it against errorwhich alone is no little gain. (33)

is not a doctrine but a 'transcendental critique' -because it aims not at the enlargement, but at the correction and guidance, of our knowledge.

This investigation, which we cannot properly call a doctrine, but only a transcendental critique, because it aims not at the enlargement, but at the correction and guidance, of our knowledge, and is to serve as a touchstone of the worth or worthlessness of all knowledge a priori, is the sole object of our present essay. Such a critique is consequently, as far as possible, a preparation for an organon... and if this new organon should be found to fail, at least for a canon of pure reason, according to which the complete system of the philosophy of pure reason, whether it extend or limit the bounds of that reason, might one day be set forth both analytically and synthetically. For that this is possible, nay, that such a system is not of so great extent as to preclude the hope of its ever being completed, is evident. (34)

is only a partial science because it is an exposition only of synthetical a priori knowledge (i.e. 'Some bodies are heavy') and not analytic a priori (i.e. 'No bachelor is married') knowledge.

But this, again, is still beyond the bounds of our present essay. For as such a science must contain a complete exposition not only of our synthetical a priori, but of our analytical a priori knowledge, it is of too wide a range for our present purpose, because we do not require to carry our analysis any farther than is necessary to understand, in their full extent, the principles of synthesis a priori, with which alone we have to do. (KANT CPR 33)

is a book that questions the possibility of ultimate knowledge on account that what counts as 'reality' is limited to our the kinds of experience we can have of it given the kinds of creatures we are. He asks 'what can we know'' And answers that human reason is necessarily limited (because of the kind of apparatus it is) to only those experiences whereby space and time can be spoken.

is the 'complete idea' of transcendental philosophy, but still not the science itself.

To the Critique of Pure Reason, therefore, belongs all that constitutes transcendental philosophy... and it is the complete idea of transcendental philosophy, but still not the science itself... because it only proceeds so far with the analysis as is necessary to the power of judging completely of our synthetical knowledge a priori. (CPR 34)

critique of pure reason, n.Definitions

critique of pure reason