So far we have said that we propose to study human experience phenomenologically, taking the objects we encounter for what they give themselves out to be, and not allowing them to be replaced by what, on some sophisticated theory of the world, really is there, or by what, on some equally sophisticated theory of the mind, really is given. We have further said that we propose to study human experience eidetically or in terms of general ideas or essences, and we have gone into some difficulties of such treatment, and have stressed its primary connection with what we called ‘logical values’ rather than with any special character of the thought-contents involved. We have also defended an eidetic treatment against many recent attacks on it, which condemn it as the typical mistake or disorder of philosophers. We have, further, refused to limit the ideas used in cave-delineation to any set arrived at by us in some special approved manner, whether by ourselves encountering an instance which illustrates such an idea, or by having such an instance pointed out to us or shown to us by others. The various forms of narrowly empiricist theories, which limit communicable ideas or meanings to what, in their last elements or forms at least, have somewhere confronted us (or will somewhere confront us) in our encounters with individuals through the senses, and which are there for others as much as for ourselves, are not made the basis of our investigations. We leave open the possibility, of which there would seem to be instances, that all of us dispose of and can use many ideas that cannot plausibly be thought part of what we encounter through the senses, though we are no doubt incited to make use of them by what is thus sensibly encountered, and that we likewise all dispose of arts, whether involving words or a mustering and manipulation of things, of inciting others to make use of similar ideas. It is perhaps better not to make use of traditional terms like ‘innate ideas’ or ‘a priori concepts’, which involve many misleading suggestions: the general possibility that they represent is, however, as unrefuted and as important as it was in the days of Descartes and Kant. Immense difficulties of course surround the notion of an unillustrable concept, which are not readily solved by such hypotheses as that of a God who imprints hall-marks on the minds of his creatures, nor by obscure manoeuvres with pure intuitions, schemata and what not. But it is a mark of a responsible philosophy never lightly to reject anything that has a colourable claim to be ‘fundamental’, merely because we have no satisfactorily shaped theory of its ‘possibility’. The full explanation of all the ideas we do have may well take us far beyond anything like ordinary human experience.

The possession of an idea, the understanding of its content—we are not conceiving ideas as anyone's personal mental act, but as ‘universals’ or ‘meanings’ that may be illustrated in instances that are not mental at all—is evinced by numerous acts of recognition, identification, practical response, etc., both overt and private, and also by the use of words in many overt and private situations. The possession of an idea in a philosophically important sense, is, however, not evinced in these primary ways, but in what we say in the quite special linguistic situations where we are engaging in philosophical enquiry or discussion. The philosophically important emergence of ideas is accordingly in dialectic, in the Socratic-Platonic sense of the word, and many ideas make their first appearance at this level. It is by what a man says when he conducts that peculiarly penetrating testing out of meanings and their interrelations that we may identify with philosophy that he reveals what ideas he disposes of and what their contents are, and he reveals this by the examples he uses, the contrasts he draws, the definitions he appeals to, the difficulties he raises, and the protests that he makes.

This must not, however, be taken to mean that the ideas important for interpreting the human cave can be mere philosophers' ideas, discontinuous from the ideas that the non-philosopher makes use of indealing with his experience, and which come out in his relatively loose verbal usages, ideas certainly having a ‘style’ quite different from those of philosophy. Obviously the human cave is the human cave, not some special asylum of precise thinkers, and the phenomena to be described in it must be things as they show themselves to persons in general and not to some special body of analysts or purists. The difficulty can be met by holding that ideas can be transformed in style without thereby, in a sense, ceasing to be the same ideas, much as happens when a piece of English is rendered into a language so profoundly different as Japanese. Provided there is both a deep desire to be loyal to the actual appearances, to the world as it gives itself out to be, and not to go behind it or explain it, and provided there is also a reasonable but not exaggerated loyalty to those logical values of clarity, simplicity, consistency, etc., which are also recognized and followed in ordinary thought and diction, then the resultant conceptual changes which occur can fairly be said to be no more than a philosophical redescription of the phenomena of human experience, rather than a revolutionary and perhaps futile attempt to go outside of it. Thus Moore, despite all his introduction of ‘sense-data’, ‘universals’, ‘acts of consciousness’ and what not, may be said, in this connection, to be not far from being a phenomenological philosopher, whereas Russell, with his notions of ‘logical constructions’, ‘neutral monism’ or the ‘theory of descriptions’ is infinitely far from being one: Aristotle, for all his abstruse talk of το τι ην ειναι or of potency and act, etc., is not far from being a philosophical redescriber of the human cave, whereas Plato often neither is one nor professes to be one. If we turn to the most conscious of phenomenologists, Edmund Husserl, we note at once that many of his conceptions are very far from ordinary. Thus the notion of intentionality, of mental directedness to objects, while founded on the ordinary grammar of mental verbs—‘I am thinking of a tortoise’, etc.—develops this grammar in ways very far from the ordinary, and introduces difficult conceptions like ‘fulfilment’, ‘categorial intuition’, ‘noematic nucleus’, etc., which astonish and repel the Anglo-Saxon reader. It is hard, indeed, for such an Anglo-Saxon reader to be told that there is more deep truth to human experience in these strange accounts than there is in many glib native utterances and expositions of an unabashedly sensationalistic or behaviouristic type. Such, however, is the case, hard-headedness and tough-mindedness and other robust virtues not always going with perceptive eyes and minds.

The paradox of the transformed, novel idea which is no less in some sense the same idea, and felt to be the same idea, as the idea out of which it develops, is a paradox that we encounter in every field of thought. Everywhere we have reflections which, while not proposing to alter anything, are yet seen afterwards as having altered what they examined, while their changed products are yet seen as having been ‘implicit’ in their origins, which leads us again to say that no change has occurred at all. This situation is of course what troubled Moore in his ‘paradox of analysis’, and is even more augustly set forth in the Aristotelian legend of two minds in us, a creative mind, always in full possession of all forms or ideas, and a passive mind which only has potential possession of them, and which can only rise to actual possession through the inspiration of its better informed neighbour. However this doctrine arose, it certainly expresses something that we deeply feel and want to say: that we refer our present ideas to some vague standard or model within themselves or ourselves, that if they fail to square with this we tidy them, and that, if they do so square, we at length achieve satisfaction and appeasement.

There is, of course, a deep distinction between what we may call the mere ‘tidying up’ of ordinary ideas and appearances, the mere freeing of them from some minor inconsistencies, and the profound revision and transformation which results in a new philosophical view of the world. The recognition, e.g., that the objects of sense-perception seem to act upon us and to make us take note of their presence and character, sheds a sharp light on a feature certainly present in ordinary experience, even if not explicitly ‘high-lighted’ or ordinarily spoken of, but such revisions as involve that action of ‘unknown causes’ upon us which is so confidently mentioned by Hume in Section II, Part I, Book I of his Treatise, obviously go far beyond the appearances. In the same way, the various inconsistencies in our notions of the relations of past, present and future, or of seeing and thinking, may permit of some minor smoothing out, but not such a revision as makes the present cover the whole of history or turns all cases of seeing into cases of thinking or vice versa. It is, of course, plain that the second sort of radical transformation is continuous with the first and merely pursues the same logical values of clarity, harmony, unity, etc., rather further—often misguidedly and unfruitfully, but not invariably and necessarily so. Things as they genuinely come before us, and not as they appear in the gleaming polish of an empiricist's show-case, certainly involve much that is obscure and internally discrepant, and that permits and calls for extensive revision: the mere fact that our talk is applied to them, is used of them, has no tendency to show that such talk is really clear and self-consistent. The ‘circumstances’ in which we use them may involve many tangled implications that quarrel with one another, as well as many half-hidden metaphysical claims to which no plain sense can be given: these may be as much part of the ‘phenomena’, the ‘data’, as what is hard-edged and clear. Moore, who is generally thought to have established the consistency and valid applicability of certain notions from the fact of usage—‘Here is one hand, and there another’, etc.—really did nothing of the sort. Moore did not think he knew he had hands because he could correctly talk of them; much more than mere correctness was involved in such knowledge, including much that was highly metaphysical and philosophically disputable, e.g. the independence of hands from anyone's knowledge of them. The fact, however, that the ‘phenomena’ of ordinary experience, and our ordinary ways of speaking of them, are in many ways obscure and discrepant, will not exempt us from giving an account of them ‘just as they are’, which brings out, and which does not attempt to lessen, their major obscurities and discrepancies. Our desire to be ‘true’ to what is before us will no doubt ultimately force us beyond this first ‘truth’ to other views and faces of things in which such obscurities and discrepancies will be eliminated, and where how things appear will accord better with what we finally feel they are, or, what is the same, with our deepest logical values. In this further revisionary development we may say, if we like, that the phenomena themselves are correcting and revising themselves or showing themselves up in their true shape, since they have no such thing as a hard given core on which such changes are imposed from without. But such deep self-correction and revision can just as well be arrested or kept within narrow bounds, and it is this arrested form of conceptual description that is characteristic of the phenomenological approach we are now considering.

All this has taken us far from Husserl's phenomenological treatment of experience, of which nothing is, on the whole, less characteristic than a clear consciousness of the ‘tidying’ necessarily involved in turning an ordinary into a phenomenological idea, of the alternative ways of carrying out such a ‘tidying’ and a careful weighing of their merits and demerits. This careful weighing of alternatives is something we encounter in the early Logical Investigations, but not in the later, explicitly phenomenological writings. These all proceed dogmatically: essences display themselves and reveal their relationships with other essences, and only at a few points is there a bringing forward of examples, or of reasons and counter-reasons. This is a place where Anglo-Saxon acuity could do valuable work. It is, however, a tribute to Husserl's phenomenological genius that, with so few arguments and reasons, he has none the less reached a balanced conceptual structure with so much ‘truth’ to the phenomena of human experience. Possibly the aim to achieve this sort of ‘truth’ pays better philosophical dividends than a blind following of the varied trends and drifts of our notions.

The exploration of the human cave consists, therefore, in an eidetic study of experience, one that considers experience in terms of the various ‘ideas’ it exhibits, and which therefore falls entirely under the Humean rubric of exploring the ‘relations of ideas’. And these ideas will have the various strongly-marked characters which ideas acquire in philosophical dialectic, and which differentiate them from the more rudely shaped, loosely structured ideas which appear in our ordinary talk and dealings. Our eidetic researches will, however, fall into two divisions, not at all clearly separable, a division in which we study what seems part of the most narrowly conceived ‘essential core’ of an idea, and a division in which we are rather concerned to find the bearings of one idea on other ideas, bearings we find it convenient to regard as in some way lying outside of the ‘core’ just mentioned and as necessarily or probably ‘consequent’ upon it. It is not at all possible nor desirable to try to obliterate the distinction just mentioned, so as to put all that follows from the central core of an idea into that idea itself, thereby making all necessitation tautologous or analytic. A distinct idea or meaning which extends over the whole of an infinite series of known or unknown transformations or consequences, and whose precise bounds are in a given case not clear at all, would be a very ill-formed notion, one certainly not fitted for human use, and perhaps too far from the ordinary notion of a notion, which conveys at least some suggestions of clearedgedness and intellectual boundedness, to be regarded as a valid case of a notion at all. And it is moreover obscurely infected with the notion of some sort of hard empirical or sensory ‘content’ which can stay the same through our conceptual gambits and manoeuvres, thereby giving them all, by its rocklike persistence, a somewhat superficial, external and dispensable character. Their eloquent differences are then really no differences at all ‘from the standpoint of the facts’. The ‘standpoint of the facts’, however, whatever its ontological merits, is not the sort of phenomenological standpoint that we are concerned to take up here, from which even a quite trivial alteration in verbal formulation, which a formal logician would carry out mechanically, may reflect a profound phenomenological variation. An object seen, e.g., as not-not-this-or-that, is not the same, qua phenomenon, as the same object seen as being-this-or-that, and an object seen as being the A of a B, is not quite the same, qua phenomenon, as the same object seen as something to which a B plays the converse relational role. For us, therefore, necessitations among the characters, essences or forms of things is what it gives itself out to be, a relation among differences which do not lose their distinctness because they shadow forth or interpret what is in a deep sense the same content. Necessitation may also only reveal itself after a long careful experimentation with certain ideas, and will not, except in a minutely narrow range of cases, be a tautological product of what we put into them.

All this does not, of course, preclude us from having two policies in the picking out of ‘ideas’ or salient phenomenal differences, one which keeps ideas as ‘thin’ and also as ‘taut’ as possible, and which does not allow them to stretch out to embrace consequential enrichments, and another which does precisely this, which keeps ideas loose and fluid, and constantly incorporates each new consequence in one growing product. The latter policy has the untoward feature of making necessitation seem trivial and tautological, and so giving rise to philosophical exaggerations, but it has the opposed towardness of avoiding the arbitrariness of deciding when to pass from the intrinsic, the essential, to the extrinsic and consequential, and of so allowing us to see things in a less strained, one-sided way. And it has, of course, the further advantage of being closer to our ordinary ideas, in which it is very often not clear that they have a central focus nor where it lies, and where a large number of alternative selections out of a loosely linked assemblage of features will be all that corresponds to an essence or core. For the special purposes of philosophy, however, the thin, taut notion has the advantage over the loose, expanding one, since by its attempted isolation and separation of notional contents, it brings their links of necessitation out into the open, while at the same time distinguishing them from merely factual linkages which are just as able to nest undiscovered in a fluid idea. For not only features that must belong together tend to be covered by the same extensible term or notion, but also features that merely do belong together, and that might quite well not have done so. And the latter have merely the phenomenological importance of being one possibility among others, whereas the former, being inescapable, are much more fundamental. Thus there are many features, e.g., of a historic type of civilization, which, it would seem, merely happen to have gone together, and which have perhaps not even the mutual affinity which would make them likely, let alone necessarily linked, associates.

We may here briefly mention, what may be relevant at a later stage of our treatment, that the ‘ideas’ which are phenomenologically relevant are not confined to such as are ideas of characters or relationships or kinds, though they can, with some violence, be forcibly seen in this mould. They are, for some part, fundamental ideas of form, such as being just this unique thing and no other, or of being exemplified or existent, or of being alternatively this or that, or of being about to be if something else is, of being the one and only thing of some sort, of consisting of something and something else, of being the difference of something from something, of having been about to be, of being permitted not to be or do something, and so on. There is no element of logical form to which an idea or notion cannot be said to correspond: if to be is in a wide sense to be the value of some function involving variables, then to be an idea is in a wide sense to be some function involving variables of which there are or may be values. The most philosophically basic of ideas are precisely those formal categorial ideas that we have illustrated, and of which Husserl had such an incomparable mastery, and which he, with absolute rightness, saw as capable of functioning in experience, though in rudimentary manner, long before the predicative symbolic level was reached. (See, e.g., Erfahrung und Urteil.) The phenomenal world is obviously full of absences, dangers, possibilities of development, aggregates, presuppositions and past backgrounds, and this long before we formulate them in language: it requires only minimal daring to concede their presence even in the phenomena revealed to animals. Language stereotypes these features of form and readily makes their logic rigid. The necessitations and exclusions which obtain among them can then be made to seem the trivial consequences of our use of words. It is important to stress that even how purely formal notions fit together is not to be decided by a consideration of language and its rules, but by an exercise of insight extending beyond it. Thus it is notional insight, not language, that must decide whether what are accounted two individuals at one time can become one individual at another, or whether there is or may or must be some individual which exists of necessity. It goes without saying that such insight involves more than the mere dwelling on the palpable sides of situations and the making of rules that accord with these and with these alone.

Nothing is easier, for instance, than to frame a system of formal diction in which the existence of something occurs as an axiom or a theorem: even Russellian logic includes the assumption that there is at least one individual of unspecified character, that there must be something of which it is at least true to say that it is either φ or not φ. (See Principia Mathematica,^∗ 22. 351.) Equally it is possible to postulate or prove the existence of some suitably specified individual like the one substance of Spinoza, or, alternatively, to construct a system in which all facts of existence have that extra-systemic contingency to which modern logic and philosophy are wedded. It is not here our task to debate or decide such an issue, but to point out that the workings of language, or even the routine operations of our concepts, are powerless to decide it, and that to construct a formal system in which it is tacitly decided is nothing but a gross imposture. The so-called neutrality of formal logic is a fiction: even to employ certain forms of predication, generalization, negation, etc., involves, both by what it permits and excludes, immense and substantial commitments, and it is important that these should be the right ones. We have to reflect deeply and to ask ourselves whether, e.g., it makes sense to suppose that there are contingents without placing them in some framework of necessary being, to ask ourselves whether there are not some matters, e.g. time, space, consciousness, divine perfection, etc., to name but a few alternatives, which it does not make sense to conceive absent. The embedded logic of language cannot decide these issues, but, once decided, it can faithfully follow the lead of our notional insight, and can even enable us ourselves to follow that lead in circumstances of confused or obscured vision.

The discovery of relations of necessitation, compatibility and incompatibility among fundamental ideas is thought to be promoted by a method of imaginative or conceptual experiment. If one can imagine or conceive examples or counter-examples, a necessity or an incompatibility can be refuted, and a compatibility demonstrated. The ‘imagining’ that is here in question may not, however, be taken to mean ‘forming an image’, for of some indispensable, valid notions we can form no image at all, whereas much of what we can form an image is not really conceivable nor capable of existing. To think otherwise is to commit a basic error of Hume, even though he as often followed the lead of his concepts as of his images. We can perfectly well have images and even sense-presentations of objects that have, e.g., extension without definite size or shape or position, that are in motion without a definite velocity, and even without a discernible change in their position. All these, as Hume rightly recognizes, are not what we should find place for in a system of reality, but they are not therefore incapable of appearing before the mind's eye. A woman wearing a gorgeous robe in public feels how she looks from every side at once: the impossibility of this visual feat does not affect the possibility of imagining it. In the same manner, it is not psychological difficulty that establishes necessity and impossibility, for we have such psychological difficulty in cases where necessity or impossibility are not judged to be present at all. The true difficulty or incapacity which leads to the grasp of a necessity or impossibility, is not, in fact, a separate experience, but the mere deep grasp itself. We become clearly aware, by way of a detailed conceptual trying out, that certain things simply can or must or cannot be.

In all this we are not so much guided by imagination and imagery as by what we may call the ‘seeing’ use of expressions. The metaphor involved in Husserl's term Wesensschau really has its use: there is a deeply understanding, ‘seeing’ use of expressions that philosophical research must build upon, and whatever device secures such a ‘seeing’ use is philosophically justified. Such a ‘seeing’ use may be achieved as we merely turn ordinary expressions over and over in a variety of contexts after the fashion of Socrates or Moore: it may also be achieved as we devise new expressions that bring out something that ordinary language largely obscures. Metaphor and poetry may direct attention to some precise point that requires illumination: sometimes we shall have to use somewhat strange, exaggerated expressions which will require frequent change to be philosophically effective. Philosophy can be conducted in completely pedestrian language, but only in cultural settings like our own where such language is often the most pregnant and pointed that anyone can use. A ‘seeing’ use of expressions is in any case profoundly different from an ordinary unseeing use, and differs profoundly in its effects. It is an immediate source of philosophical questions and answers, which will carry us on to a telling description of things as they actually seem or are given to us, as also, by raising hidden difficulties and obscurities, to those sweeping reidentifications and notional realignments that will concern us later.

It is here that we encounter the need to extend the relations of ideas in a noteworthy manner. Ideas, it may be held, do not merely entail or exclude or suffer one another, they may also be favourable or unfavourable to one another, and in differing degrees. There are, if one likes, a priori, notional probabilities and improbabilities as much as there are a priori, notional necessitations, incompatibilities and compatibilities. Notional compatibility among ideas in fact differentiates itself into varying degrees of notional favour or disfavour, the upper limit of the former being notional necessitation, and of the latter notional incompatibility. The suggestion we are now making astonishes in our present climate of opinion, where probability has become more and more stripped of its notional trappings, and made more and more a wholly factual, empirical matter, being even identified with an actually ascertained frequency or a presumed limiting frequency of occurrence. With such sophisticated empiricism we are not here concerned to argue. Probability is an irremovable feature of the human, and, we may add with confidence, even of the animal cave, and as such it resists reduction to anything factual, anything ascertainable and discoverable, anything that is or could be merely there. Its home lies on the dark fringe of the unclear where reason spins her web of conjecture and makes her hazardous stands: it is above all a second-order modal notion, no more capable of having observable first-order instances than its sister modalities of pastness or potency. Probably doing or being something is not a particular way of doing or being something, any more than having done or been something, or being able to do or be something, can be regarded as such. The older notional treatment of probability in fact abounded in a priori elements, and one could not establish any empirical probabilities except in a general framework of what was probable a priori. We are, however, not here concerned with the probability of highly specific complex events, such as the drawings of balls from urns, set in elaborate backgrounds of conditions, but with probabilities of extremely high generality, connecting notions of fundamental importance in the human cave. It is these probabilities, or these relations of intrinsic favourableness or unfavourableness, that we must hold to be among the most interesting and the most regrettably neglected of all the ‘relations of ideas’ needed in studying the phenomena of the human cave.

If one feels an initial strangeness in the claim that there are such probabilities—the realm of ideas is after all thought to be a timeless realm of essences, bound together by timeless relations, and therefore, it would seem, by relations of pure necessity—one has but to consider a few cases to have this impression corrected. (Or rather, if one likes, to see that there are necessary probabilities as well as necessary necessities.) This is particularly the case if one considers phenomena into which mind enters, though it can be said to characterize non-mental phenomena also. We may here consider a few connections involving belief, which we may take as it gives itself out to be, a phenomenon involving deference to an order of things that impinges on us compulsively, as it were, or is felt as threatening to do so—we shall find out how things are, and how they are will have nothing to do with us—and which is quite unlike those patterns of ideas that we can manipulate arbitrarily or which at least represent our drifts and our interests. Belief so conceived certainly involves, as something growing out of though not strictly part of its content, a readiness to sway feeling and action in quite definite ways, but it is none the less only a readiness, and it is not at all absurd that such a tendency should be absent in a given case. Hence all the modern theories from Bain to Braithwaite which have defined belief in terms of a readiness for action, theories that embody undoubted notional insight, but admit equally of undoubted exceptions. Believing in the reality of something that one also desires is, further, certainly favourable to rejoicing in it, and unfavourable to grieving over it or being indifferent to it, but the collocations in question are likewise not excluded by the nature of belief. Believing that something one desires is actual is wildly unfavourable to continuing madly to strive for it, but one would hesitate to say that they were quite incompatible. Believing something is likewise intrinsically favourable to wanting others to believe it, and to believing that they will do so, though less plainly so than in the previous cases, just as believing that others do not believe something is intrinsically unfavourable to believing it oneself. None of these connections give themselves out as being merely empirical: it is not merely because one has found them obtaining repeatedly in the past that they enjoy their present likelihood. This likelihood appears to have the seal of ‘right reason’ upon it; as a phenomenon, it seems rooted in the ‘natures’, the ‘ideas’ under examination. The same appears even if we turn to connections that have a strong empirical smack: they seem to presuppose, as has been often pointed out, some inherent principle of persistence, of continuance along the same or similar courses, what is same or similar being a matter of direct insight and not merely of symbolic convention. All science and scientific philosophies have been full of principles of conservation, the simpler principles having a greater inherent likelihood, and the less simple only entering the lists when the more simple have been worsted. And while non-conservation or simple ‘emergence’ has sometimes to be faced, it can be faced only because it does not always encounter us, and in facing it we feel that we not only encounter a difficulty in believing, but also a difficulty in being. The sheerly emergent, the genuinely miraculous can happen, but not, we feel, very often.

Sophisticated theory, with its blindly masochistic attitude to experience, in the sense of individual encounter, and its unwillingness to limit its self-submission at any point short of the formally self-contradictory, is inclined to see in all these advance probabilities mere reflections of our human make-up, whose justification is at best heuristic or pragmatic. We do not know, it is said, but we guess: formally the possibilities espoused in scientific theory are always flanked by infinitely many alternatives, and therefore are, and remain, infinitely unlikely. This, upon certain restricted, unordinary definitions of the probable, is perhaps an arguable position. From our less formal, less scientific point of view, it may however be said that the world qua phenomenon is not given as a system poised between infinitely many, equally weighty alternatives, concerning which nothing at all is evident, but as a world whose general character and course is at every point clear, though there is indefinite room for painting in details. To learn by experience is to get to know a thing or kind of thing better, to learn more about a person or about persons generally, to penetrate further into the vast space around us, to see whether this or that is a matter of law or chance, etc. All these descriptions indicate that the sort of thing or situation we are about to find out about is well known to us and that what we find out will only make this specific. And in a sense all this is wholly as it should be. All enquiry, Aristotle rightly says, springs from prior knowledge, and we could not frame questions, nor hope to answer them, if we were always wandering in some desperate ‘cloud of the unknowing’ in which absolutely anything might suddenly loom up at us. But from another reflective point of view it does indeed appear strange that we should have all this remarkable advance knowledge of what is also given as being quite independent of us, as not being conditioned by our thinking nor made to fit it. The problem of the substantial a priori is indeed one of the deepest riddles of the cave.

If there are relations of notional probability such as we have mentioned, then philosophy, though a study of the relations of ideas, can also derive profound illumination from experience, and can likewise give it to experience. The fact that A and B are displayed together in empirical encounters, may challenge us to find a notional connection among them, though this may not at first be at all obvious. Though at first it appears mere matter of fact that A and B go together, deeper reflection may show them to have an affinity which renders this but to be expected. Thus the relation between certain feelings and certain expressive motions may reveal itself on reflection to be not the merely factual relation that to superficial insight it gives itself out to be, but one that has something essential about it. Contrariwise, a seeming relation of essence may derive confirmation from the fact that certain factors do go together, just as it may be weakened, though not necessarily abolished (since the relation may be one of probability) if they do not. This situation resembles one in which recurrent sequences suggest the presence of causal connection, except that the latter has a much larger admixture of the sheerly empirical than the former.

The notion that experience and a priori affinity may throw mutual light on one another has been used by many philosophers in considering the facts of nature or history, e.g. Hegel, Whitehead. What is found to be the case is used to suggest conceptual alignments of a non-contingent kind, and vice versa. This way of proceeding arouses great dismay in certain quarters, where it is axiomatic that what we learn by examining ideas is tautological and not substantial, and that all substantial information derives from experience, in the sense of individual encounter. On such presuppositions, the a priori and the a posteriori necessarily exclude one another. This axiom is, however, absurd, since even in the realm of the strictly necessary, many demonstrable truths, e.g. that the sum of the first n odd numbers always is a perfect square, may be suggested empirically, and the same holds of many instances of a priori truths, e.g. that having spent five of the ten pennies originally in my pocket, I shall now find only five pennies there. If empirical facts can promote insight into a priori connections in these cases, how much more will they do so in cases where the a priori connections in question are merely probable, and admit of empirical exceptions. Hegel, we may note, freely admits the merely probable character of many of the dialectical connections in his system, since he frequently reminds us that a notional connection is not refuted by occasional empirical exceptions. (Though such exceptions are called by him ‘low and untrue existences’, etc.) Husserl, on the other hand, admits absolutely no element of the merely probable into his phenomenology, and it is arguable that this prejudice in favour of the strictly necessary frequently distorts his insight. Again and again connections which are certainly not mere contingencies, but which also have actual or thinkable exceptions, have to be given the false status of absolute necessities, since no other is available. Many of the exaggeratedly portentous generalizations found in phenomenological and existentialist writings owe their origin to this prejudice.

We may here hold generally that it is the business of the philosopher, as it is that of the scientist, to advance the claims of the necessary and the intrinsically likely, and to push back the sphere of mere matter of fact as far as may be. The philosopher wishes to understand, to see factors hanging together in bonds of mutual requirement, and this means that he must be in quest of relations of mutual necessitation and probabilification even in the most unpromising coincidences. This does not mean that the philosopher must imagine that pure matter of fact can ever be completely liquidated. Pure matter of fact is the necessary foil to the necessary, or to the intrinsically likely, without which the latter would certainly lose their dignity and even their meaning. That some connections must obtain only seems to make an intelligible point on a background of other connections that need not obtain. Universal internal relations differ little from universal external relations. Nor does it mean that the philosopher may not welcome the real or imagined counter-examples which refute a hastily asserted necessity or near-necessity. Such counter-examples are, in fact, the philosopher's element of control: they are as welcome to him as are crucial instances to the scientist. The philosopher may in fact open his arms to as many possibilities as are genuinely conceivable: he may like Russell invoke logic to give him wings rather than fetters. But the granting of wings in some cases is only valuable if it goes with the acceptance of fetters in others, and of fetters more restricting than are prescribed by a mere logic of non-contradiction.

We are here brought to a concluding view of the method of our investigation which again brings in dialectic, but this time not the dialectic of Socrates and Plato, of which Husserl's eidetic phenomenology is a remote descendant, but the somewhat different, mobile dialectic of Hegel. I should perhaps apologize to you for having first made you endure so much dry exposition regarding ideas and their relations and now, in this last section of my lecture, submerging everything previously said in flux. The suggestion to be considered is, however, that the ideas in terms of which the human cave is to be seen should not be a single set of notions, tidily set forth and fixedly related to one another, but a set of notions that undergoes perpetual revision and perpetual deepening, that repeatedly withdraws from itself, as it were, to a new level of reflection and insight, from which it suddenly is able to pass remarkable judgements on what it previously judged and saw, and to see in its previous views implications that were not at all evident at their own level. Things that, on a first view, seemed utterly different may, on a second view, reveal no difference that is worth mentioning, whereas things that on a first view seemed independent may on a second view show themselves as deeply dependent on each other, and a prima facie dependence of A on B may on a deeper examination reveal itself as more truly a dependence of B on A. More paradoxically, cases may arise when a notion looked at from an outside vantage-point may imply or exhibit the very opposite of its explicit content, may be empty when it claims concreteness and fulness, may really differentiate when it claims to unify, or unify when it claims to differentiate, may through its application refute the very things that its application seems to involve. Dialectic on this view is not a sort of one-level clarification and development of our notions, but a clarification and development that involves what we may call higher-order comment, self-criticism from a perpetually shifted meta-standpoint, so that what is clear and fixed at one level of consideration may be quite transformed and shifted at the next. The human cave, on this view, cannot be described by a single unvarying phenomenology, but only by a series of such phenomenologies: the phenomena, we may say, themselves develop and alter as we consider them, and may, in the end, transform the cave into something that can no longer be counted as a cave at all.

The kind of moving dialectic we are considering is only vaguely present here and there in Husserl, as where he passes from a Cartesian suspension regarding the objective world to something that looks uncommonly like Berkeleyan idealism. But it is, as we have said, the characteristic thought-method of Hegel, where it goes with a deeply interesting doctrine of three mental functions. We have, first, a function which isolates and fixes, and which makes notional contents seem quite independent of other notional contents, as belonging to a different sphere, as having nothing to do with other notional contents, and as requiring them neither for development nor contrast—this first function is called by Hegel ‘Understanding’. Then we have a second function which realizes that the separatist system just instituted is deeply absurd, that it really presupposes the things it excludes, and that things cannot meaningfully be credited with the character given to them except in the setting provided by other seemingly external, irrelevant factors—the second function is called by Hegel ‘Dialectic proper’. Finally, in the Hegelian dialectic, we have the third thought-function which he calls ‘Reason’ or ‘Speculation’, whose function it is elaborately to undo the neat isolation and fixation which has been the work of the first thought-function, while yet preserving the distinctions which the first thought-function has introduced. We proceed to notions which are not featureless blurs, but which are systematic wholes characterized by what Hegel calls ‘totality’, which means simply that each member of the system presupposes all the others, and may be said to have a built-in reference to the others in its notion, so that we have in reality not a set of separate notions, but a single notion seen, as it were, from distinct and perhaps opposed standpoints. We then also pass from whole notional systems of greater separateness and mutual irrelevance to systems of ever-increased interdependence, until, it is suggested, some absolute limit is reached. The systems of greater interdependence depend, however, on those of lower interdependence, in that, only when ideas have, as it were, made their separate bow, can they be integrated as ‘sides’ of a single more inclusive unity. And as we go up the series the grammar of our language changes also: we start with statements having common-or-garden correctness and end up with statements worthy of the mystics, that the ordinary man finds puzzling and self-contradictory.

I cannot here justify all these astonishing ideas, as little fully appreciated in our own age as in previous periods. I can only stress, for the moment, that they are not self-contradictory, that they are not at variance with the phenomenological approach of these lectures, and that they may prove illuminating in our researches. There is nothing self-contradictory in holding that we may have continuously to revise and deepen the notions in terms of which we see the world, and that our initial notions often only make sense as one-sided, stylized abstractions from what we shall later feel impelled to employ. Nor are notions and forms of speech which differ in grammar and conceptual style from less developed notions and forms of speech, and which make no sense and even suggest self-contradiction from the standpoint of the latter, necessarily self-contradictory; the boot may well be on the other foot. Again, we are not trying the undermine the loyalty to the appearances which constitutes the sheet-anchor of the phenomenological method. The appearances, if you like, may be disloyal to themselves: they may, like reversible diagrams or puzzle pictures, reveal new emphases when one considers them intently. It can be argued, lastly, that the revisionary treatment we are proposing can be very illuminating, and of this I shall give only two examples. It is extremely illuminating, when we first reflect on our notions of time and its passage, to stress the mutual exclusiveness of the parts of time, the impossibility that they should exist together, since, as we say, the presentness of the one means that the other is no longer present but is past, or is not yet present but future, and yet do we not in a sense refute ourselves out of our own mouths when we say this? For, if the past is not part of the present, is this exclusion, this pastness of that past not part of the present, not something that now is the case, something without which, moreover, the present would have no position and only a vanishing content, and does not this in a fashion readmit the past, encapsulated and modified, no doubt, into the present that thus excludes it? And do we not therefore pass from a time in which events lie outside of one another, the natural way of viewing the matter, to a time which is always present in toto, though differently stressed and filled? In the same sort of way might we not progress from a natural world which is quite independent of the observer to a natural world whose independence is so much the foil of the observer's approaches, and so much fitted to be such a foil, that its independence becomes a sort of dependence? If these examples seem highly coloured, shall we refer to Gödel's proven unprovability of a certain formalized sentence in one formalized language, which is at the same time the provability and actual proof of the same sentence considered from the standpoint of another higher language? If respectability is what is wanted, there are many examples in modern mathematics and mathematical logic which illustrate the real, rather than the falsified, text-book method of Hegel.

It is not our task in this preliminary lecture to pronounce on the viability or validity of some method like the Hegelian. Its value will be established, if it is established, as we run through various phases of cave-life, and see whether or not it actually is the case that the notions these involve fail to make sense unless organically related to other notions, in which organic relation they are not quite the same notions (though of course not wholly different notions) from the notions they were before. Hegel, as careful students will know, only made use of his dialectic to establish a vastly enriched humanism and this-worldism, in which das Jenseitige, that which seems to lie beyond the cave, is brought wholly within the compass of human experience, so that human rationality when raised to the fully self-conscious forms of art, religion and philosophy, simply becomes the all-explanatory raison d'etre of everything. Other philosophers, both earlier and later, have, however, used something like Hegel's dialectic to go beyond the confines of the human cave. Plato and Plotinus have used alleged discrepancies in ordinary modes of conceiving things to draw us up towards higher realms of being, Spinoza made use of an ‘intuitive science’ to take us beyond the mutilated perspectives of ordinary experience, and Bradley, clad in a loosely woven robe of Hegelian and Spinozistic fibres, rose by dialectic to a strange type of purely sentient experience which he said was that of the Absolute. Our study of the phenomena may force us to make a similar ascent, and there is nothing in our view of ‘experience’, ‘ideas’, ‘necessitation’, etc., which precludes it. There is nothing in the notion of an ideal content or idea which entails that it can never do more than organize the grossly given, that it cannot point to a completion, even an empirical completion, beyond present gross experience. Relations of ideas go beyond the strictly necessary, and cover matter that may be a real issue in experience: the notion of a speculative extension from this world into some other cannot therefore be excluded a priori. It may be that the truly critical treatment of our notions will necessarily end by being through and through speculative, that one will not understand anything grossly before one until one sees it in a context of what is not thus grossly given, and which perhaps, in some cases, never can be. And possibly, once we have made our excursions into ‘the beyond’, a further deepening of insight may lead us to say that no excursion has been involved after all. All this cannot, however, be asserted at this stage: we shall have to go on with our detailed examination of the cave of human experience. We shall begin on this detailed examination in the next lecture by considering the bodies which, as we metaphorically said, occupy the foreground of the human cave.