A priori

“ The dualism between concept and sensation, between the a priori and the a posteriori, between thought and thing, between form and matter, is not given in experience, for in experience the formal and the material are one inseparable whole; it is the product of cognition. ”

“ Thus all knowledge which asserts existence is empirical, and the only a priori knowledge concerning existence is hypothetical, giving connections among things that exist or may exist, but not giving actual existence. ”

“ The forms under which the critical method is applied—such as the distinctions between a priori and a posteriori elements in cognition, between matter and form, between phenomena and noumena, between sense, understanding, and reason—ought not to disguise from us the true nature of the question which underlies all of them. ”

“ We can be sure, he says, that anything we shall ever experience must show the characteristics affirmed of it in our a priori knowledge, because these characteristics are due to our own nature, and therefore nothing can ever come into our experience without acquiring these characteristics. ”

“ In his view, unless a thing was not merely conceivable, but even explainable, it could not exist in nature. All natural phenomena, according to him, must be susceptible of being accounted for a priori. ”

“ There is no doubt that the object of a pure conception either of the understanding or of reason, so far as it is to be estimated philosophically and on a priori principles, can in this way be completely known. ”

“ If the intuition must conform to the nature of the objects, I do not see how we can know anything of them a priori. If, on the other hand, the object conforms to the nature of our faculty of intuition, I can then easily conceive the possibility of such an a priori knowledge. ”

“ Since, therefore, in the cases which lay the strongest claims to be examples of knowledge a priori, the mind proceeds from the idea of a thing to the reality of the thing itself, we can not be surprised by finding that illicit assumptions a priori consist in doing the same thing erroneously; in mistaking subjective facts for objective, laws of the percipient mind for laws of the perceived object, properties of the ideas or conceptions for properties of the things conceived. ”

“ That is, being and existence, in the relation of cause and effect, are presented, and affirmed to reason, as the one complex object of its original intuition, and its constitutive idea.
This is the point of co-incidence of the a priori and a posteriori arguments, demonstrating the Christian theistic conception. They analyze the synthetic judgment of reason, and show its contents. The argument, a priori analyzes it on the side of being, showing what is contained in being, or ens. The argument a posteriori analyzes it on the side of existence, existentia. ”

“ The reason a priori is, the infinite nature of the Divine Mind, the immeasurable scope and activity of the Divine understanding, which wholly comprehends, penetrates and perfectly beholds all things, even those that are the most secret, and what is called the liberty of man, and his free thoughts and volitions. ”

“ As I do not wish this critical essay, the sole purpose of which is to treat of the sources of our synthetical cognition a priori, to be crowded with analyses which merely explain, but do not enlarge the sphere of our conceptions, I reserve the detailed explanation of the above conceptions for a future system of pure reason. ”

“ But there is also an a priori aspect of thought, where by a mediation, not made by anything external but by a reflection into self, we have that immediacy which is universality, the self-complacency of thought which is so much at home with itself that it feels an innate indifference to descend to particulars, and in that way to the development of its own nature. ”

“ 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. ”

“ In order that the human intellect may not appear transcendental, in order to give it its place in the general classification of natural forces, we must investigate the nature of causality and so-called a priori knowledge. ”

“ Whether these general principles are given a priori, as the intuitionists hold, or whether they are the abstract expression of an experience invariably and unconditionally repeated, at all events they must be such that from them all our scientific theories may be deduced; they must appear in all our researches as the criterion of the truth of the results, and they must underlie all our anticipations of truth as the guiding principles. ”

“ This brings us to a second charateristic of philosophical propositions, namely, that they must be a priori. A philosophical proposition must be such as can be neither proved nor disproved by empirical evidence. Too often we find in philosophical books arguments based upon the course of history, or the convolutions of the brain, or the eyes of shell-fish. Special and accidental facts of this kind are irrelevant to philosophy, which must make only such assertions as would be equally true however the actual world were constituted. ”

“ For one thing, we have found that every step towards Truth is a step away from vague possibilities, and towards determinateness of idea and of experience. Our very ideas themselves, even when expressed as hypotheses, or as universal definitions, or as a priori mathematical constructions, or as judgments of hypothetical or of universal type, are from the outset destructive of vague possibilities, and involve Determination by Negation. ”

“ It is, however, true that without antecedent experience we can cognize and characterize the possibility of things, relatively to the formal conditions, under which something is determined in experience as an object, consequently, completely a priori. ”

“ Prior to the perception of the thing, however, and therefore comparatively a priori, we are able to cognize its existence, provided it stands in connection with some perceptions according to the principles of the empirical conjunction of these, that is, in conformity with the analogies of perception. For, in this case, the existence of the supposed thing is connected with our perception in a possible experience, and we are able, with the guidance of these analogies, to reason in the series of possible perceptions from a thing which we do really perceive to the thing we do not perceive. ”

“ So that every cognition, or idea, or perception, necessarily consists of two parts, the one of which is native to the mind, and is often denominated a priori—to indicate that it is the essential or grounding element; and the other of which is extraneous to the mind, and is frequently termed a posteriori, to signify that it is the changeable, or accidental, or accruing element It is thus obvious that the doctrine of innate ideas, when properly understood, is merely another form of the doctrine advanced in the first proposition of the epistemology ”

“ Pure general logic has to do, therefore, merely with pure a priori principles, and is a canon of understanding and reason, but only in respect of the formal part of their use, be the content what it may, empirical or transcendental. ”

“ In general, however, we are a priori conscious of nothing more than the principle of sufficient reason in its different forms, and therefore no other synthetic judgments a priori are possible than those which proceed from that which receives its content from that principle. ”

“ If we reason a priori, anything may appear able to produce anything. ”

“ But how such a proposition, which appears so greatly to extend our knowledge of nature, is possible completely a priori, is indeed a question which deserves investigation, although the first view seems to demonstrate the truth and reality of the principle, and the question, how it is possible, may be considered superfluous. ”

“ The fact that a strictly empirical philosophy was taken by so many critics to imply an a priori dogma about the kind of consequences capable of existence is evidence, I think, of the inability of many philosophers63 to think in concretely empirical terms. ”

“ As applied to matters of experience, it is analytic rather than constructive; taken a priori, it shows the possibility of hitherto unsuspected alternatives more often than the impossibility of alternatives which seemed primâ facie possible. Thus, while it liberates imagination as to what the world may be, it refuses to legislate as to what the world is. ”

“ That is to say, we shall consider the logical form of the cognition of reason, that we may see whether reason may not be thereby a source of conceptions which enables us to regard objects in themselves as determined synthetically a priori, in relation to one or other of the functions of reason. ”

“ In respect of Mind and its works, just as in the case of Nature, we must guard against being so far misled by a well-meant endeavour after rational knowledge, as to try to exhibit the necessity of phenomena which are marked by a decided contingency, or, as the phrase is, to construe them a priori. ”

“ It is open to us to believe that the ideal elements exist, and there can be no reason for disbelieving this; but unless in virtue of some a priori law we cannot know it, for empirical knowledge is confined to what we actually observe. ”

“ The belief in physical causation, assumed from moment to moment as necessary in every experiment and in all reasoning from it, is a belief which, if not justified by the hypothesis above set forth, is tacitly asserted as an a priori belief. ”

“ If he reasons in the former of these ways, he forms a priori such a conception of matter that it would involve a contradiction to suppose that the phenomena occasioning the dispute should inhere in it; he first of all fixes for himself a notion of matter, as of something with which certain phenomena are incompatible, something in which they cannot inhere; and then from this conception he deduces the inference that these phenomena are incompatible with matter, or cannot inhere in it—a petitio principii almost too glaring to require notice. Or does he reason upon this question a posteriori? ”

“ The question whether we have not some knowledge independent of any and all experience — whether there must not, unavoidably, be some knowledge a priori, some knowledge which we come at simply by virtue of our nature — is really the paramount question, around which the whole conflict in philosophy concentrates, and on the decision of which the settlement of every other question hangs. ”

“ For us, the knowledge, the creative identity, is second, while in reality it is the first. Our consciousness cannot be partly a priori and partly a posteriori, nor one of the two, but must be both at once, and each entirely. ”

“ We judge, for example, that happiness is more desirable than misery, knowledge than ignorance, goodwill than hatred, and so on. Such judgements must, in part at least, be immediate and a priori. Like our previous a priori judgements, they may be elicited by experience, and indeed they must be; for it seems not possible to judge whether anything is intrinsically valuable unless we have experienced something of the same kind. ”

“ There can be nothing more desirable to a philosopher, than to be able to derive the scattered multiplicity of the concepts or the principles, which had occurred to him in concrete use, from a principle a priori, and to unite everything in this way in one cognition. ”

“ For I find myself unable to form the slightest conception of a thing which when annihilated in thought with all its predicates, leaves behind a contradiction; and contradiction is the only criterion of impossibility in the sphere of pure a priori conceptions. ”

“ For without this observation it would be quite impossible to make out whether the intuitions of space and time, which we borrow from no experience, and which yet lie in our representation a priori, are not mere phantasms of our brain, to which objects do not correspond, at least not adequately, and consequently, whether we have been able to show its unquestionable validity with regard to all the objects of the sensible world just because they are mere appearances. ”

“ If any one thinks himself offended, he is at liberty to refute my charge by producing a single synthetical proposition belonging to metaphysics, which he would prove dogmatically a priori, for until he has actually performed this feat, I shall not grant that he has truly advanced the science; even should this proposition be sufficiently confirmed by common experience. No demand can be more moderate or more equitable, and in the (inevitably certain) event of its non-performance, no assertion more just, than that hitherto metaphysics has never existed as a science. ”

“ This is therefore the result of all our foregoing inquiries: "All synthetical principles a priori are nothing more than principles of possible experience," and can never be referred to things in themselves, but to appearances as objects of experience. And hence pure mathematics as well as a pure science of nature can never be referred to anything more than mere appearances, and can only represent either that which makes experience generally possible, or else that which, as it is derived from these principles, must always be capable of being represented in some possible experience. ”

“ The distinction of ideas, that is, of pure concepts of reason, from categories, or pure concepts of the understanding, as cognitions of a quite distinct species, origin and use, is so important a point in founding a science which is to contain the system of all these a priori cognitions, that without this distinction metaphysics is absolutely impossible, or is at best a random, bungling attempt to build a castle in the air without a knowledge of the materials or of their fitness for any purpose. ”