Intuition

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INTUITION

The broadest definition of the term intuition is "immediate apprehension." Apprehension is used to cover such disparate states as sensation, knowledge, and mystical rapport. Immediate has as many senses as there are kinds of mediation: It may be used to signify the absence of inference, the absence of causes, the absence of the ability to define a term, the absence of justification, the absence of symbols, or the absence of thought. Given this range of uses, nothing can be said about intuition in general. Instead, it is necessary to pick out those principal meanings of the term that have played the most important roles in philosophical controversy and to discuss each of these individually.

Four principal meanings of intuition may be distinguished: (1) Intuition as unjustified true belief not preceded by inference; in this (the commonest) sense "an intuition" means "a hunch." The existence of hunches is uncontroversial and not of philosophical interest. (2) Intuition as immediate knowledge of the truth of a proposition, where immediate means "not preceded by inference." This is a philosophically important sense, since philosophers have found it puzzling that one can have knowledge, and thus justified belief, without having made oneself aware through the process of inference of any justification for this belief. (3) Intuition as immediate knowledge of a concept. "Immediate knowledge" here means, roughly, "knowledge that does not entail ability to define the concept." (4) Intuition as nonpropositional knowledge of an entity—knowledge that may be a necessary condition for, but is not identical with, intuitive knowledge of the truth of propositions about the entity. This sense of intuition is exemplified by (a ) sense perceptions, considered as products of a cognitive faculty distinct from the faculty of forming judgments concerning the entity sensed; (b ) intuitions of universals, or (as in Immanuel Kant) of such insensible particulars as time and space—intuitions that are necessary conditions of our intuitive knowledge of a priori truths; (c ) mystical or inexpressible intuitions that, unlike sense perceptions and intuitions of universals, do not make possible knowledge of the truth of propositions about the entities intuited—such intuitions as Henri Bergson's inexpressible intuition of duration, Johann Gottlieb Fichte's intuition of the Transcendental Ego, and the mystic's intuition of God.

Faculty and Linguistic Explanations of Intuitive Knowledge

intuitive and noninferential knowledge

There is both a strong and a weak sense of "intuitive knowledge that p." In the weak sense of this term, S knows that p intuitively if (a ) p is true, (b ) he is justified in believing that p, and (c ) his knowledge that p is not based upon his inferring p from other propositions. The criterion for its not being so based is simply that S would deny, for any set of propositions p * from which p follows, that he believes that p because he believes that p * (although he might in fact believe p * and be willing to adduce p * to satisfy someone else's doubts about p ). In this sense of "intuitive," we may know intuitively that we have two legs or two children, but we cannot know intuitively that the Civil War was caused by slavery, or that nothing can move faster than the speed of light. In this sense, the existence of intuitive knowledge is unquestionable; and "intuitive" in this sense is synonymous with "noninferential."

In the stronger sense of intuition, however, only a certain species of noninferential knowledge is intuitive: S knows that p intuitively only if (a ) p is true, (b ) he is justified in believing that p, and (c ) there are no accepted procedures for resolving doubts about the truth of p, given S 's belief that p. Thus we may be justified in believing without inference that we have two legs, but if we have doubts we can undertake such tests as looking and seeing, asking others, and checking the possibility of collective hallucination. Given these tests, so much evidence may appear to show that one leg is missing that it would be irrational to maintain our previous belief. But in certain cases—for example, our belief that we are in pain, or that every event has a cause—there are (at present) no procedures available for resolving doubt. It is never irrational to continue to believe that S has a pain once one knows that he believes he does, despite, for instance, the failure of physiologists to find a concomitant neural process. Again, if someone thinks that some events are uncaused, we have no way of testing his hypothesis. Yet we are not willing to give up our claim to know that he is wrong. In both sets of cases—so-called rock-bottom data of perception and introspection, and so-called unquestionable first principles—justified belief is accompanied by the lack of procedures to settle doubt. These are the two paradigm cases of "intuitive knowledge," in the strong sense of the term—first-person statements about those psychological states to which one has "privileged access" and underived a priori truths.

In this stronger sense, too, the existence of intuitive knowledge is unquestionable. Two points should, however, be noted. First, if in formulating the conditions for the application of this sense of intuitive knowledge we had simply said "p is indubitable" rather than "there are no accepted procedures for resolving doubts about p," then it would have been questionable whether any such knowledge existed. It can plausibly be argued that, under sufficiently peculiar circumstances, it may be rational to doubt one's belief that one is in pain, or that every event has a cause. In general, it can plausibly be argued that there are no intrinsically indubitable propositions, for rational doubt may outstrip the possibility of rationally settling doubt. Second, it is possible for procedures to come into existence for settling doubt in areas where none existed before. Thus we now take S 's belief that he was in pain as the best possible evidence for his having been in pain, but advances in physiology may bring about a practice of withdrawing claims to have been in pain when the relevant neural processes have failed to occur. Under these conditions, S 's belief that he was in pain would be intuitive in the weak sense, but no longer in the strong sense. Again, some philosophers would argue that, with the rise of quantum theory, we are now in a position to treat "every event has a cause" as an empirical hypothesis, even though it was once the paradigm of an unquestionable first principle. In general, whether a proposition can count as the object of intuitive knowledge (in the strong sense) is a function of the availability of accepted procedures for settling doubt, and it is doubtful that we can know a priori in what areas such procedures will and will not be developed.

Noninferential will here be used in place of the weak sense of intuitive, and intuitive in place of the strong sense. Both noninferential and intuitive knowledge seemed to philosophers to require explanation because the paradigm of knowledge has, since Aristotle, frequently been taken to be inferential knowledge—the case in which one knows not only that p is true but also why p is true, and believes that p is true because one believes certain other propositions from which p may validly be inferred (see Aristotle's Posterior Analytics I, 2). Noninferential knowledge has often been explained by being assimilated to this paradigm through the use of the notion of implicit or unconscious inference. Cases of nonintuitive knowledge have been treated as cases in which an inference from intuitively known premises was performed, and cases of nonintuitive, noninferential knowledge as cases in which the knower is not aware of having performed the appropriate inference.

faculty theory

Various explanations have been given of the existence of intuitive knowledge. As was noted, the objects of intuitive knowledge seem to fall into two quite different groups—such very particular facts as "This looks white" or "This hurts," and such very general facts as "Every event has a cause" or "If p implies q, and p, then q." Our knowledge of the particular has often been referred to as sensory intuition, and of the very general as nonsensory intuition. The simplest, most familiar, and least helpful explanation of our possession of these two sorts of intuition is that we possess faculties which produce such knowledge. Accepting this explanation amounts to granting that the presence in our mind of the original starting points of knowledge is inexplicable and must be accepted as a brute fact. Aristotle was content with this solution, and so was René Descartes. In Cartesianism this inexplicability was woven into the fabric of a metaphysical dualism, according to which no mental event (such as a coming-to-know) could be caused by any sequence of physical events, and in which the only mental relation that could bring about a coming-to-know was the relation of being inferred from. This picture of the mind required that comings-to-know which were not preceded by inference be treated as uncaused causes, incapable of explanation.

Descartes's extreme rationalism led him to insist that sensory intuitions are not really cases of knowledge at all, and this in turn led him to hold that they are not really mental events but merely physical ones. Thus he did not recognize two intuitive faculties (one sensory and one nonsensory) but only one, the nonsensory. In his view, sense perception is in principle nonessential to attaining complete knowledge, although it is mysteriously necessary in practice. This paradoxical position was criticized by John Locke and others. Under the impact of such criticisms, a more moderate rationalistic position was developed, according to which both sense perception and the intellect are sources of genuine knowledge and enjoy equal status as intuitive faculties.

linguistic theory

The new moderate rationalism was attacked by the immoderate empiricism of David Hume, according to which our only intuitive faculty is that of sensory intuition. Hume, however, and such later empiricists as Bertrand Russell, continued to accept the Cartesian metaphysical framework, thus admitting that no explanation can be given of the fact that a physical event p (the modification of one of S 's sense organs) is frequently followed by the mental event M (S 's coming-to-know that p ). They insisted, however, that an explanation can be given of the acquisition of our nonsensory intuitive knowledge and that consequently it is not necessary to postulate a special faculty that provides us with knowledge of first principles. The alternative explanation (in the form it was given by the logical positivists) was that all such knowledge is knowledge of analytic truths and that the process of acquiring such knowledge is identical with the process of learning the conventions of one's language. This view—sometimes called the linguistic theory of a priori knowledge—held that to know, for example, that all events are caused is simply to know something about the meanings of the words event and cause, and that this knowledge is acquired by easily understandable processes of psychological conditioning. To this suggestion, rationalists objected, first, that the process of learning the meaning of cause cannot be accounted for except by invoking a special faculty of intuitive acquaintance with universals; and, second, that the linguistic theory represents a confusion of acquiring knowledge with acquiring the ability to express this knowledge.

prelinguistic knowledge

The rationalists held, concerning the linguistic theory, that even granted that it would be a violation of linguistic conventions to speak of "uncaused events," the real question is: How do we know that this is the right convention to adopt? Is not this latter piece of knowledge, knowledge of nonlinguistic fact? Are not linguistic conventions adopted on the basis of such prelinguistic knowledge? Such questions, many philosophers thought, show that the linguistic theory does not enable us to dispense with a faculty of nonsensory intuition. As long as the central presupposition of these questions—that S can properly be said to know that p prior to his ability to express p in language—was granted, this rationalist rebuttal created a new deadlock.

The influence of Cartesianism, and particularly of the Cartesian notion of sense perception as a special, unanalyzable mental act correlated with certain modifications of sense organs, made it difficult to question this presupposition. Sense perception was, it seemed to most philosophers, a clear example of our ability to know facts without having the ability to express them. If a child, by virtue of his faculty of sensory intuition, can see that a physical object O has the sensory quality Q by a simple, uncaused act, prior to acquiring the ability to express this fact in language, then why cannot the same child see with his mind's eye that every event has a cause and, on the basis of this prelinguistic intuitive knowledge, check the correctness of conventions concerning the words cause and event ?

behaviorist analysis

The notion of prelinguistic knowledge, and with it the whole Cartesian conception of comings-to-know as mental occurrences, was questioned by Gilbert Ryle, Ludwig Wittgenstein, and their followers. Under the influence of these writers, many philosophers have come to treat "S knows that p " not as a statement about S 's mind but as a statement that, besides presupposing the truth of p, asserts that S is disposed to assert p on appropriate occasions, and also either that S is prepared to give good reasons for believing that p or that S is justified in believing p even though he is unable to give reasons for believing that p. The last case covers all noninferential knowledge, both intuitive and nonintuitive. In the case of S 's nonintuitive, noninferential knowledge—that, for example, he has two children, or that there is a house in front of him—the criteria that establish that S is entitled to assert these propositions are of two sorts: those that determine whether he knows the meanings of the terms he uses and those that determine whether his situation and abilities are normal (where normal means, roughly, that the sincere reports of persons with these abilities in these situations are usually confirmed when checked by independent means). For example, S would be justified in believing that there is a house in front of him if he knew what a house is (that is, knew what house means), had his eyes open, and had normal vision. He would be justified in believing this even if, when asked, "How do you know that that's a house?" he was too unsophisticated to make any reply except "I just know." Whether S satisfies these criteria can be determined by public procedures—testing his grasp of the language, his vision, and his position vis-à-vis the house in straightforward and unmysterious ways.

According to the Cartesian view, what justifies S in believing p in the absence of an ability to produce good reasons for believing p is a special, private, introspectable mental state. S introspects to see whether or not he knows that p, and thus he knows intuitively that he knows that p and has better ground for the belief that he knows that p than anyone else can have. The behaviorist alternative asserts, on the contrary, that the fulfillment of public criteria is not just an external symptom of the presence of an occult mental state called knowledge, but that the statement of such criteria gives a full account of the meaning of "to know." This treatment of such cases of nonintuitive, noninferential knowledge as "I see that O is Q " is designed to replace the Cartesian notion of sense perception as a simple, unanalyzable act with the view that to see that O is Q cannot happen prior to the ability to use correctly the terms O and Q (or some equivalent expressions). Infants and animals, confronted by O, have sensations but do not have perceptions. They begin to perceive that O is Q when these sensations, and only these sensations, are accompanied by a disposition to assert or assent to "O is Q." Thus, they begin to perceive that O is Q only when their belief that O is Q becomes a reliable indicator of the truth of "O is Q."

This behaviorist analysis of nonintuitive, noninferential knowledge can be used to explain the difference between this case and the case of intuitive knowledge. The difference is that in the case of intuitive knowledge the only criterion that S must satisfy in order to be entitled to believe p without being able to offer good reasons for p is that he knows his language. The paradigms of intuitive knowledge—knowledge of "private" psychological states and knowledge of underived a priori truths—are such that if a person claims knowledge of this sort, the only way in which his claim can be refuted is to show that he does not know his language. For example, if someone sincerely believes that he is in pain, we cannot show that his belief is mistaken unless (as in the case of a young child) we can show that his use of pain is idiosyncratic. Again, if someone claims to know that every event has (or does not have) a cause, we cannot show that his belief is unjustified unless we discover that he does not understand what he is saying (and we discover this by discovering that his use of event or of cause is idiosyncratic). To know what one is saying is, in certain cases, to know that what one says is true.

Behaviorist analysis also permits an explanation of our possession of intuitive knowledge that dispenses with the notion of intuitive faculties. In the case of sensory intuition, the process of acquiring intuitive knowledge is simply the occurrence of certain sensations in a person who knows a language that contains ways of describing these sensations (that is, contains expressions whose utterance speakers of the language are conditioned to correlate with occurrences of these sensations). In the case of nonsensory intuition, we acquire intuitive knowledge simply by reflecting upon our own linguistic behavior (where reflecting means, roughly, "asking ourselves questions about what we would say if …"). In both cases, the crucial precondition is knowledge of a language, and the process of acquiring this knowledge is taken to be a matter of psychological conditioning—conditioning whose operations are explicable entirely in terms of a stimulus-response model. Whereas according to the traditional Cartesian faculty view the difference between men and animals is a matter of man's possession of a special sui generis power (variously called awareness, consciousness, spirit, reason, and the like), this difference is regarded by many contemporary philosophers as a matter of the ability (due, presumably, to a more complex central nervous system) to respond in more diverse ways to a wider variety of stimuli—as a matter of degree rather than of kind.

cartesian and wittgensteinian attitudes

The difference between Cartesian and Wittgensteinian attitudes toward the fact that intuitive knowledge that p, such that belief in p is justified yet there is no way to settle doubt about p, exists may be summed up by saying that for a Cartesian the claim that belief in p is justified must reflect a natural fact—for example, some intrinsic feature of that belief (considered as a mental state), such as self-evidence. For the Wittgensteinian, this claim need reflect only a social convention. On the Cartesian view, it is only contingently true that we possess intuitive knowledge, a fact that is to be explained (if at all) by reference to the makeup of our minds. On the Wittgensteinian view, our possession of intuitive knowledge is a necessary truth, built into the use of the word know. The Cartesian reasons that since there cannot be an infinite regress—and thus justification of beliefs must stop somewhere—there must be certain kinds of belief that are intrinsically of a special sort, such that to have them is to know that they do not require justification. Followers of Wittgenstein reason that since there can be no infinite regress—and thus justification of belief must stop somewhere—one would expect, given our use of the word know to mean "justified belief," that there would be certain conventions dictating that certain beliefs are justified even in the absence of good reasons. For the Cartesian, these conventions reflect introspectable facts about the mind or about entities (such as universals) visible to the eye of the mind; for the Wittgensteinian, they do not reflect anything. To ask why we have procedures for settling doubt about S 's claim that he sees a house, although we do not have procedures for settling doubt about his claim that he has a pain, is, according to Wittgensteinians, to ask why we use the words pain, house, and see as we do. To such questions there is no answer. Nor is there any answer to the question why we use event or cause in such a way that it does not make sense to ask whether or not a given event was uncaused. We just do. That in certain cases it does not make sense to ask certain questions—for example, the question "How do you know?"—is, on this view, as much a matter of convention as the fact that one normally says "I am in pain" when being tortured but not when being caressed.

objections to the linguistic explanation

Much contemporary epistemological controversy consists of arguments for and against the behaviorist analysis of knowledge and the linguistic explanation of intuitive knowledge. The principal objections to the linguistic explanation are three: (1) It has been claimed that no behavioristic analysis of believes (and thus a fortiori of knows ) can be achieved without recourse to terms that, like believes itself, exhibit intentionality. (2) It has been argued that the view that there is no awareness, perception, consciousness, or knowledge prior to the acquisition of linguistic ability makes it impossible to understand how we can learn language in the first place. (In rebuttal, it has been argued that to suppose that we learn how words are used by associating certain awarenesses with certain utterances is a misleading backward projection of the way in which an adult learns new words into the original learning of language by the child.) (3) It has been argued that the stimulus-response model is inadequate for explaining the learning of languages, on the ground that one who knows a language is able to produce grammatical sentences he has never heard. This fact has suggested to some theorists that we must postulate innate knowledge in order to explain language-learning.

This entry will not attempt to resolve these issues, but will only describe how the linguistic explanation has been brought to bear upon (a ) the notion of unconscious inference, (b ) the notion of intuitive awareness of universals, and (c ) the notion of nonpropositional knowledge.

Noninferential Knowledge and Unconscious Inference

It has traditionally been held that all knowledge that is not intuitive is inferential, and thus that the cases of nonintuitive, noninferential knowledge should properly be regarded as the products of unconscious inference. This view is most familiar in the form of the phenomenalist claim that S 's knowledge that, for instance, there is a white house before him is always the result of an inference from propositions concerning the sense data that S is currently having or concerning the appearances that the house is presenting to him. Proponents of this view regard S 's denial that he made such an inference or believed such propositions simply as evidence of a lack of philosophical sophistication. Such a view results from the assumption that only certain special propositions are suited, by virtue of their intrinsic properties, to be objects of noninferential knowledge. Thus, phenomenalists hold that "That is a white house" is inherently unsuited to be noninferentially known, whereas "I am now having a white sense datum" or "There now seems to me to be something white in my visual field" is inherently suited to be so known. The occurrence of an unconscious inference in S, they hold, is guaranteed by the fact that his belief is unsuited to be an expression of direct sensory awareness. No empirical evidence is allowed to disconfirm that such an unconscious inference was performed.

The criterion for being an expression of direct sensory awareness used by sense-datum theorists usually takes one or the other of the following forms:

p expresses S 's direct sensory awareness if and only if S has intuitive knowledge that p (if, in other words, there are no procedures available that would provide better evidence against p than the fact of S 's belief that p provides for p ), and if S 's coming to know that p is correlated with S 's having a certain sensation.
p expresses S 's direct sensory awareness if and only if a sufficient condition of the acquisition of knowledge that p by S is that S has a certain sensation (so that none of S 's antecedent knowledge interferes to provide an interpretation of what his senses give).

These two criteria are often taken as interchangeable by philosophers who have gone in quest of the "given" elements in experience—for, at first blush, such intuitively knowable propositions as "I am in pain" or "I seem to be seeing something white" seem the most promising candidates for satisfying the second form.

The linguistic explanation of sensory intuition attempts to dispense with both the given and unconscious inference. According to the linguistic theory nothing could possibly satisfy the second form, since a sensation is never a sufficient condition for the acquisition of a bit of knowledge. Also, there is nothing paradoxical in saying that a man may simultaneously come to know, without performing any inferences, that this is an airplane, a Boeing airplane, and a B-29 as a result of a single modification of the eyes—the same modification that, in a child, would produce only the knowledge that this is something silver. According to this theory, the man's belief in all these propositions is justified because, roughly speaking, he has been conditioned to utter statements expressing each of them when certain sensory stimuli are received. Some men, as we say, just know a B-29 when they see one, and others do not. An aircraft spotter trained to respond to the appearance of a B-29 by saying "There is a B-29" would have a justified belief in this proposition even if he were unable to list any criteria for B-29-hood (and thus were unable to provide any reasons for his believing the plane to be a B-29).

For those who accept a linguistic explanation of intuitive knowledge, the traditional attempt to identify noninferential and intuitive knowledge by means of the notion of unconscious inference results from a confusion of the context of S 's acquisition of the knowledge that p with the context of his justifying his belief that p to one who doubts p. If an argument between S and a doubter of an empirical proposition p were carried to its ideal limit, S might eventually have to retreat to such intuitively known statements as "It seems to me that I remember that q " and the like. The ideal empiricist would be the man who never believes an empirical proposition p unless he has previously performed an inference embodying the argument that he would give in defense of p when challenged by a die-hard doubter. (The ideal empiricist, in other words, is the ideal Cartesian doubter; he always doubts every proposition he knows how to doubt.) The notion that we are all unconsciously ideal empiricists is a confusion of "S would not be able to justify his belief that p to a die-hard doubter without appealing to certain propositions that he knows intuitively to be true" with "S is not justified in believing p if he has not previously so justified his belief to himself."

Once we adopt the linguistic explanation of intuitive knowledge, its defenders argue, we see that whereas noninferential knowledge is a matter of one's disposition to make certain statements being a sufficient ground for one's belief that they are true, intuitive knowledge is a matter of that disposition serving as the best possible evidence for their truth. The propositions that can be noninferentially known by S, like those that can be intuitively known by him, are determined by S 's training, circumstances, and abilities, together with the conventions in force within his linguistic community. The fact that certain propositions are usually known noninferentially, and others usually known intuitively, by normal adults has misled philosophers into thinking that certain special intrinsic properties belong to all those propositions, and only to those propositions, properties detectable by our mental eye. The linguistic theory, freeing us from the "mental eye" model, directs our attention to the factual criteria that we use in deciding whether a certain belief, held by a certain person, is justified.

Intuitive Acquaintance with Concepts

A person is said to have intuitive acquaintance with a concept if he is able to understand a large range of propositions that employ a term signifying this concept and is unable to explain the significance of this term. Thus (confining ourselves, for the sake of simplicity, to descriptive concepts) we may say that S grasps F-ness intuitively if and only if he can use the expression "F" correctly, and he does not know any noncircular definition of "F," where a "definition of 'F'" is any true statement of the form "X is called 'F' (or 'an F') if and only if it is ______," and "noncircular" means that the blank is filled by some expression that neither contains "F" nor contains any word whose definition itself contains "F," nor any word whose definition contains words whose definition contains "F," and so on.

act of abstraction theories

As in the case of intuitive knowledge that p, there is no dispute among philosophers about the existence of intuitive acquaintance with concepts. Rather, as in the former case, controversy arises concerning the explanation of this fact. In this case also, philosophers working within a Cartesian tradition accept a "simple act" theory. On this traditional view, we possess a faculty called abstraction that, for example, peels the whiteness of white objects from these objects and holds the whiteness up before our mental eye; once we have whiteness clearly in focus, we can label it with the term white and thus can acquire a knowledge of how to use this term. This act of abstraction, like the act of intuiting that p, is specifically mental, simple, and unanalyzable. Within this Cartesian framework, the principal issue is that between rationalists and empiricists: Whether such a simple act of abstraction must be postulated to explain only our knowledge of apparently indefinable sensory concepts (like "white"), or whether it is also needed to explain our knowledge of apparently indefinable nonsensory concepts, such as "being," "cause," "necessity," or "good." Empiricists have traditionally held that these latter concepts are not grasped intuitively. They have claimed either that our knowledge of how to use terms signifying them is a result of our implicitly or unconsciously possessing noncircular definitions of them, or that these terms do not refer to concepts at all but are without meaning. Consequently, they have devoted themselves to proposing such definitions, or to developing theories of meaningfulness that would permit the conclusion that these terms have no meaning. Rationalists, on the other hand, have insisted that certain terms signify a priori concepts, and that none of the definitions of these terms proposed by empiricists (such as Hume's definition of causation as "constant conjunction") are adequate.

linguistic theory of conceptual intuition

The traditional account of our intuitive grasp of concepts contains many of the same elements as the traditional view of intuitive knowledge that p. It is again assumed that we need to account for a difference between humans and animals (the fact that we can use concepts, whereas animals can merely respond to stimuli) by postulating a simple sui generis mental act and that this simple act does not occur in all the cases that, prima facie, are cases of immediate knowledge, but that some such cases are cases of unconscious mediation. Just as recent philosophical thought has turned away from the notion that intuitive knowledge that p is to be regarded as such a simple act, and has offered an account of the acquisition of such knowledge in terms of a theory according to which the use of language is a necessary condition of the possession of any piece of knowledge, recent thought has likewise asserted that the ability to use "F" correctly is all that is signified by the phrase "acquaintance with F-ness," and thus that the notion of a prelinguistic grasp of F-ness is incoherent. According to this newer view, no object of acquaintance (such as a concept, conceived of as a sort of mental particular) need be postulated as that with which language learners correlate utterances of general terms. We learn such terms as white not by correlating utterances of them with anything but by being subjected to a conditioning process that leads us, after some trial and error, to utter these words in appropriate contexts in appropriate situations. This process need not, at any stage, involve our knowing the truth of any proposition of the form "X is called 'F' only when it is an instance of F-ness."

The older view, in insisting on the necessity of such knowledge, assumes that the process of learning the use of an indefinable word such as white must parallel the process of learning the use of a word by learning its definition. Just as we might correlate utterances of "bachelor" with situations in which we would be inclined to say "unmarried male," and thus learn the meaning of "bachelor," so (the older theory holds) we correlate utterances of "white" with situations in which we are aware of whiteness. But, proponents of the newer view object, the only test we have for knowing whether we are aware of whiteness is whether or not we are inclined to utter "white." Nothing is added to an explanation of learning words ostensively by a reference to acquaintance with concepts, save the unverifiable claim to possess a piece of prelinguistic knowledge. If this newer view (largely due to Wittgenstein and his followers) is accepted, then what distinguishes us from the animals is not that they cannot perform the mysterious operation of intuiting concepts but simply that we can respond in much more various ways to a much greater variety of stimuli than they can (and, specifically, we can develop patterns of linguistic behavior). Once again, the difference between humans and animals reduces to the possession of language.

One advantage claimed by defenders of this newer view is that, if it is accepted, the old controversy about the existence of a priori concepts that divided rationalists from empiricists is rendered moot. The question of whether we must postulate a sort of nonsensory ostention of such concepts as causality, or an innate grasp of them, no longer arises if the same sort of process that enables us to learn the use of white enables us to learn the use of cause. To acquire the concept of causality is, on this view, to learn the use of the word cause ; this can be done without correlating utterances of cause with anything, but simply by trial and error: Sometimes when we say "This caused that," we are rebuked, and sometimes praised, until gradually we get it right. (Before we got it right, we were said not to know the meaning of cause, just as we were said not to know the meaning of white as long as we called "white" what our parents called "gray.") The question of whether cause (and other terms that have been held to signify a priori concepts) is definable without circularity now loses its philosophical interest.

Intuition as Nonpropositional Knowledge

The final sense of intuition comes primarily from Kant, who defined "intuition" as "knowledge that is in immediate relation to objects" (see Critique of Pure Reason, A19–B34, A320–B377). By immediate he here meant "without the mediation of concepts," and he took sense perception as the paradigm of intuition (although he also argued for the existence of pure intuitions of space and time). Kant sharply distinguished immediate knowledge from knowledge of the truth of judgments concerning the objects sensed, since he held that the formation of judgments requires the addition of concepts to intuitions. The former sort of knowledge is a necessary condition of the latter. The knowledge gained in sense perception is expressed by judgments concerning the objects sensed but exists prior to the formation of these judgments. Perceptual knowledge of O is, on this view, not reducible to knowledge that O has certain properties.

This distinction between immediate knowledge of objects and mediate knowledge of facts about these objects was formulated by Russell, in The Problems of Philosophy, as the distinction between "knowledge by acquaintance" and "knowledge by description." He proceeded to explain a priori knowledge by postulating a faculty, analogous to sensation, that acquaints us with universals and with the relations between universals. The assertion of the existence of universals has, traditionally, gone hand in hand with the faculty explanation of our intuitive knowledge of a priori truths and of our grasp of nonsensory concepts. It is still current among contemporary philosophers who resist the linguistic explanation of this knowledge. These philosophers include both such traditional rationalists as Brand Blanshard and phenomenologists who adopt Edmund Husserl's notion of intuition of essences.

The Kantian notion of sense perception as a kind of nonjudgmental knowledge has had the effect of opening the door to the suggestion that we possess a certain sort of knowledge that is like sense perception, or Russellian acquaintance with universals, in being immediate but unlike either in being inexpressible. In other words, it is suggested that we have an intuition of a certain object O even though we do not know the truth of any proposition of the form "O is Q." The reason usually given for our failure to have the latter sort of knowledge is that conceptual thought (or language) is inadequate to capture the essence of X. For example, Bergson argued that duration cannot be captured by concepts (nor, a fortiori, expressed in language) because concepts (and thus language) are designed precisely to freeze and stabilize (and thus to distort) the flux of experience, whose essence is duration. Again, God's perfect simplicity—his identity with his own attributes—is held to make it impossible truly to apply any predicate to him, and thus to know any true propositions about him.

Philosophers who adopt the view that there is no knowledge prior to the possession of language, and who construe knowledge in the behavioristic manner, naturally object to the notion of nonpropositional knowledge. On their view, the original Kantian notion of sense perception as a kind of knowledge is based upon a confusion. Once this confusion is dissipated, the analogy to sense perception that is the basis of Russellian accounts of a priori knowledge and of theories of inexpressible intuition will no longer be available, and the notion of knowledge of O that is irreducible to the knowledge that O has certain features will appear as paradoxical as it really is. The original confusion, these philosophers argue, is that of the cause of the belief that some sensed object O has the feature Q with the justification of this belief. Specifically, the fact that knowledge that O is Q is caused by a sensation of O is combined with the assumption that nothing can serve to justify S 's claim to know about O except another piece of knowledge about O by S. This produces the conclusion that the mere sensing of O is itself a case of knowing—distinct from, because giving a ground for, the knowledge that O is Q. Since sensing O is construed as a direct relation between the knower and O, whereas knowing that O is Q is construed as a relation between the knower and something distinct from O (a fact or a proposition), it is inferred that there are two sorts of knowing, one of which is primitive and direct and the other derivative and indirect. A causal condition for knowledge is thus confused with a special type of knowledge—knowledge by acquaintance.

Philosophers who deny the existence of such nonpropositional knowledge by acquaintance argue that the notion of knowledge of O that is not knowledge that O has some feature is neither present in ordinary usage nor part of a useful explanatory theory. On their view, all knowledge of objects is knowledge of the truth of propositions about these objects. This anti-Kantian position is supported by, and supports, the anti-Cartesian behaviorist position, according to which knowledge cannot occur prior to the ability to learn language. Although it is logically possible to hold both that there can be prelinguistic knowledge of facts and that there is no such thing as knowledge of particulars as distinct from knowledge of facts, this position is not popular. Contemporary epistemological thought is, by and large, split between those who adopt both a Cartesian "simple act" explanation of the intuitive knowledge that p and a Kantian notion of nonpropositional knowledge as a necessary condition for intuitive propositional knowledge, and those who reject both of these views in favor of a radically behavioristic approach.

Intuition of the Inexpressible

Even philosophers who have remained faithful to the traditional Cartesian and Kantian positions tend to criticize the use of the notion of intuition as nonpropositional awareness made by such philosophers as Fichte, Bergson, and contemporary Thomists. Their criticism is based on the view that the only criterion for knowing whether S has nonpropositional knowledge of O is his knowledge of the truth of propositions about O. Thus both groups reject claims to have knowledge that one is unable to express (except, perhaps, in analogies and metaphors). Anti-Cartesian philosophers, however, argue that it is precisely the Kantian view that sensing is a kind of knowing that opens the gates to claims to intuit the inexpressible. This view leads naturally to the conclusion that even the objects of ordinary sensory acquaintance are incommunicable and inexpressible. No amount of talk by Jones (who has seen O ) will suffice to reproduce in Smith (who has not) the sensation Jones had when he was in the presence of O. This failure to reproduce an experience is, given the view that sensing is a kind of knowing, taken as a failure to convey knowledge of O, even though Smith may learn, from Jones's reports, every fact about O that Jones knows. We thus find ourselves adopting a novel, and peculiarly philosophical, sense of "express"—a sense in which an experience would be expressed only if it were reproduced. Whereas in the normal sense of the term, my seeing a white house is completely and adequately expressed by some finite set of such propositions as "That's a white house," in this new sense such propositions are inherently unsatisfactory surrogates. This line of thought, opponents of nonpropositional knowledge argue, plays into the hands of those who, like Bergson, hold that language is inadequate to reality.

The claim that language is inadequate to express one's intuitive knowledge of reality would, in itself, be harmless. However, the danger of adopting this new meaning of "inexpressible" is that we may find ourselves claiming private justification for our moral, philosophical, religious, aesthetic, or other beliefs by saying, "Although I cannot, of course, express (or communicate or put into words) the experience that I had, and hence cannot supply you with reasons for believing that p, I am nevertheless entitled to believe that p solely on the strength of that experience." The plausibility of this sort of reasoning stems from the fact that, in the case of noninferential belief about physical objects, we sometimes say things like "Since you haven't seen a flying saucer, you have no reason to believe that there are flying saucers; but I have seen one, and so I do believe in them." Here we seem to be justifying a belief solely on the basis of private experience. The difference is that "I saw a flying saucer" is a complete and adequate expression of this experience, in the ordinary sense of "express." The justification is sufficient because the statement that an experience E was had analytically implies p. (If S saw a flying saucer, then there are flying saucers to be seen.) In the former case, however, the statement that an experience E was had cannot entail any statement about the object of the experience because the nature of the experience is, ex hypothesi, inexpressible.

This obvious disanalogy is veiled by the fact that in the second, philosophical sense of "inexpressible," our experiences of seeing houses or flying saucers are just as inexpressible as the Thomists' intuition of Being, or Bergson's intuition of duration. In other words, a tacit shift to a new sense of "express" creates the sophistical argument "Since your sensory experiences are inexpressible, and yet sufficient to justify your beliefs, it is unfair of you not to let my inexpressible nonsensory experiences justify my beliefs." Of course, in the ordinary sense of "express," sensory experiences are as expressible as experiences can be.

In addition to this criticism of the ambiguity contained in the philosophers' use of "inexpressible," a further criticism of such claims to private justification is available if the behaviorist view of the nature of justification of claims to noninferential knowledge is adopted. If this justification is viewed not as a matter of an intrinsic, introspectable property (self-evidence) of certain beliefs but rather as a matter of social convention, then one will hold that we know which of our noninferential beliefs are justified only by knowing which ones our peers would agree are justified. In the flying saucer example, we rightly think that our belief in flying saucers is justified if we think we have seen flying saucers, because we are confident that anyone who had had the sensations we have had would have been disposed to utter "I see a flying saucer." We know that our belief is justified because our peers admit that if they should ever have an experience of the sort we claim to have had, they would share our belief. The only element of privacy lies in the fact that they can have doubts about, for example, whether we are being truthful in claiming that we had this experience, or whether we were sober, or attentive, whereas we cannot.

In the "inexpressible intuition" case, however, we cannot tell whether our peers would share our belief if they shared our experience, for we do not know what our experience was. Here we could speak of a private justification only if we had a private language in which we could express to ourselves, although to no one else, what we experienced, and private criteria of justification formulated (in part, at least) in this private language. But, aside from the general difficulties in the notion of a private language pointed out by Wittgenstein, "private criteria of justification" is an intrinsically paradoxical notion. One can no more have private rules for justifying beliefs than one can have private rules for justifying actions. A criminal has no greater claim on our sympathy if he proclaims that his private ethical code differs from ours, and a believer in untestable beliefs has no greater claim on our attention when he says that his epistemological code is not ours.

See also Intentionality; Objectivity in Ethics.

Bibliography

The medievals used "intuitive cognition" as we would use "sensory intuition" to refer to knowledge about objects present to the senses. The term was opposed to "abstractive cognition," which included memory and imagination. They also, however, used "intuition" to refer to a vision of God. This use of "intuition" for any sort of knowledge that has the same noninferential character as knowledge of the apparent features of an object present to the senses was continued by Descartes (Regulae XII), Benedict de Spinoza (Ethics II, Prop. 40, Note 2), and Locke (Essay concerning Human Understanding, Book II, Ch. 2, Sec. 1). These philosophers used the term as we would use "nonsensory intuition"—to refer to our noninferential knowledge of, for instance, mathematical axioms and analytic truths, and of the validity of valid inferences. Between Descartes and Kant, "intuition" was rarely used in reference to perceptual knowledge, nor was a clear distinction made between propositional and nonpropositional knowledge. Since Kant, however, it has been usual to speak of both nonpropositional perceptual knowledge of a particular, and of the propositional knowledge derived from this nonpropositional knowledge, as cases of intuition.

Whereas Kant had denied the existence of intellectual intuition (nonpropositional knowledge of insensible objects), Fichte asserted it in his Werke, edited by I. H. Fichte (Berlin, 1845), Vol. I, pp. 463ff. However, Fichte argued that he did not really disagree with Kant because the object of this intuition, the Transcendental Ego, was an act rather than a thing. The same strategy is adopted by contemporary neo-Thomists, who speak of an intuition of Being; what is intuited, they say, is an act rather than a thing or an essence. See Jacques Maritain, Existence and the Existent (New York: Pantheon, 1948), Ch. 1, and Étienne Gilson, Being and Some Philosophers (Toronto: Pontifical Institute of Mediaeval Studies, 1949), Ch. 6. The most influential recent proponent of a faculty of nonpropositional knowledge other than sense perception is Henri Bergson; see his Introduction to Metaphysics (New York: Putnam, 1913). For a criticism of Bergson's notion of intuition, consult G. Watts Cunningham, A Study in the Philosophy of Bergson (New York: Longmans Green, 1916), Ch. 3. For a discussion of the philosophical importance of the ineffable intuitions claimed by mystics, see W. T. Stace, Mysticism and Philosophy (New York, 1960), Chs. 1 and 3.

W. H. Walsh, Reason and Experience (Oxford: Clarendon Press, 1947), contains an account of traditional controversies between rationalists and empiricists concerning intuitive knowledge. For the traditional view that intuitive knowledge of facts about objects sensed is based on a nonpropositional acquaintance with these objects, see Bertrand Russell, The Problems of Philosophy (London: Williams and Norgate, 1912), Ch. 5. Criticism of the notion of knowledge by acquaintance, which Russell develops in The Problems of Philosophy, is found in H. L. A. Hart, "Is There Knowledge by Acquaintance?" in PAS, Supp. 23 (1949): 69–90; also see the essays by G. E. Hughes and J. N. Findlay on the same topic in the same volume, 91–128, and Wilfrid Sellars, Science, Perception, and Reality (London, 1963), pp. 127–196. Additional criticisms of the view that sensing is a form of knowing occur in H. A. Prichard, "The Sense-Datum Fallacy," in PAS, Supp. 17 (1938): 1–18; Wilfrid Sellars, "Physical Realism," in Philosophy and Phenomenological Research 15 (1954–1955): 13–32; and Gilbert Ryle, The Concept of Mind (London: Hutchinson, 1949), Ch. 7.

The notion of unconscious inference is presented in Bertrand Russell, The Problems of Philosophy, Ch. 13, and a defense of this notion in Gilbert Harman, "How Belief Is Based on Inference," in Journal of Philosophy 61 (1964): 353–359. For the criteria of direct sensory awareness, see Bertrand Russell, "On Verification," in PAS 38 (1937–1938): 1–20. Russell's Analysis of Mind (London: Macmillan, 1921), Ch. 12, states the view that beliefs are introspectable mental occurrences. For criticism of this view, see Gilbert Ryle, The Concept of Mind, Chs. 2 and 5. The view that we can introspectively differentiate knowledge from mere belief is found in H. A. Prichard, Knowledge and Perception (Oxford, 1950), p. 88. Prichard is criticized on this point by Norman Malcolm in his Knowledge and Certainty (Englewood Cliffs, NJ: Prentice-Hall, 1963), p. 58.

For the contemporary reaction to Cartesianism, see Gilbert Ryle, The Concept of Mind, and Ludwig Wittgenstein, Philosophical Investigations (Oxford: Blackwell, 1953). An earlier reaction against the Cartesian account of intuitive knowledge is C. S. Peirce's Collected Papers (Cambridge, MA: Harvard University Press, 1933–1958), Vol. V, pp. 135–189. For the linguistic account of intuitive knowledge of the truth of propositions, see Wilfrid Sellars, Science, Perception, and Reality, pp. 164–170. The view that intuitive knowledge of a priori truths is founded upon a nonpropositional knowledge of universals or essences is found in Bertrand Russell, Problems of Philosophy, Ch. 10; Brand Blanshard, Reason and Analysis (La Salle, IL: Open Court, 1962), Chs. 6, 9, 10; and Edmund Husserl, Ideas (New York: Macmillan, 1931). For critical discussion of this view and of the linguistic account of a priori knowledge, see Arthur Pap, Semantics and Necessary Truth (New Haven, CT: Yale University Press, 1958).