This suggests that a strictly monistic epistemology, whether idealistic or realistic, does not get rid of the problem. Suppose for example we take a sensationalistic idealism. It does away with the ontological gulf between ideas and facts, and by reducing both terms to a common denominator seems to facilitate fruitful discussion of the problem. But the problem of the distinction and reference (agreement, correspondence) of two types or sorts of sensations still persists. If I say the box there is square, and call "box" one of a group of ideas or sensations and "square" another sensation or "idea," the old question comes up: Is "square" already a part of the "facts" of the box, or is it not? If it is, it is a supernumerary, an idle thing, both as an idea and as an a.s.sertion of fact; if it is not, how can we compare the two ideas, and what on earth or in heaven does their agreement or correspondence mean? If it means simply that we experience the two "sensations" in juxtaposition, then the same is true, of course, of any casual a.s.sociation or hallucination. On the sensational basis, accordingly, there is still a distinction of something "given," "there," brutally factual, the box, and something else which stands on a different level, ideal, absent, intended, demanded, the "square," which is a.s.serted to hold good or be true of the thing "box." The fact that both are sensations throws no light on the logical validity of any proposition or belief, because by theory a like statement holds of every possible proposition.[53]
The same problem recurs on a realistic basis. For example, there has recently been propounded[54] the doctrine of the distinction between relations of s.p.a.ce and time and relations of meaning or significance, as a key to the problem of knowledge. Things exist in their own characters, in their temporal and spatial relations. When knowledge intervenes, there is nothing new of a subjective or psychical sort, but simply a new relation of the things--the suggesting or signifying of one thing by another. Now this seems to be an excellent way of stating the logical problem, but, I take it, it states and does not solve. For the characteristic of such situations, claiming to terminate in knowledge, is precisely that the meaning-relation is predicated _of_ the other relations; it is referred to them; it is not simply a supervention existing side by side with them, like casual suggestions or the play of phantasy. It is something which the facts, the qualitative s.p.a.ce and time things, must bear the burden of, must accept and take unto themselves as part of themselves. Until this happens, we have only "thinking," not accomplished knowledge. Hence, logically, the existential relations play the role of fact, and the relation of signification that of idea,[55] distinguished from fact and yet, if valid, to hold _of_ fact.
This appears quite clearly in the following quotation: "It is the ice which means that it will cool the water, just as much as it is the ice which does cool the water when put into it." There is, however, a possible ambiguity in the statement, to which we shall return later.
That the "ice" (the thing regarded as ice) _suggests_ cooling is as real as is a case of actual cooling. But, of course, not every suggestion is valid. The "ice" may be a crystal, and it will not cool water at all. So far as it is already certain that this _is_ ice, and also certain that ice, under all circ.u.mstances, cools water, the meaning-relation stands on the same level as the physical, being not merely suggested, but part of the facts ascertained. It is not a meaning-relation as such at all. We already have truth; the entire work of knowing as logical is done; we have no longer the relation characteristic of reflective situations. Here again the implication of the thinking situation is of some "correspondence" or "agreement"
between two sets of distinguished relations; the problem of valid determination remains the central question of any theory of knowing in its relation to facts and truth.[56]
II
I hope this statement of the difficulty, however inadequate, will serve at least to indicate that a functional logic inherits the problem in question and does not create it; that it has never for a moment denied the prima facie working distinction between "ideas,"
"thoughts," "meanings," and "facts," "existences," "the environment,"
nor the necessity of a control of meaning by facts. It is concerned not with denying, but with understanding. What is denied is not the genuineness of the problem of the terms in which it is stated, but the reality and value of the orthodox interpretation. What is insisted upon is the relative, instrumental, or working character of the distinction--that it _is_ a _logical_ distinction, inst.i.tuted and maintained in the interests of intelligence, with all that intelligence imports in the exercise of the life functions. To this positive side I now turn.
In the a.n.a.lysis it may prove convenient to take an ill.u.s.tration of a man lost in the woods, taking this case as typical of any reflective situation in so far as it involves perplexity--a problem to be solved.
The problem is to find a correct idea of the way home--a practical idea or plan of action which will lead to success, or the realization of the purpose to get home. Now the critics of the experimental theory of logic make the point that this practical idea, the truth of which is evidenced in the successful meeting of a need, is dependent for its success upon a purely presentative idea, that of the existent environment, whose validity has nothing to do with success but depends on agreement with the given state of affairs. It is said that what makes a man"s idea of his environment true is its agreement with the actual environment, and "generally a true idea in any situation consists in its agreement with reality." I have already indicated my acceptance of this formula. But it was long my misfortune not to be possessed offhand of those perfectly clear notions of just what is meant in this formula by the terms "idea," "existence," and "agreement" which are possessed by other writers on epistemology; and when I a.n.a.lyzed these notions I found the distinction between the practical idea and the theoretical not fixed nor final, and I found a somewhat startling similarity between the notions of "success" and "agreement."
Just what is the environment of which an idea is to be formed: i.e., what is the intellectual content or objective detail to be a.s.signed to the term "environment"? It can hardly mean the actual visible environment--the trees, rocks, etc., which a man is actually looking at. These things are there and it seems superfluous to form an idea of them; moreover, the wayfaring man, though lost, would have to be an unusually perverse fool if under such circ.u.mstances he were unable to form an idea (supposing he chose to engage in this luxury) in agreement with these facts. The environment must be a larger environment than the visible facts; it must include things not within the direct ken of the lost man; it must, for instance, extend from where he is now to his home, or to the point from which he started. It must include unperceived elements in their contrast with the perceived. Otherwise the man would not be lost. Now we are at once struck with the facts that the lost man has no alternative except either to wander aimlessly or else to _conceive_ this inclusive environment; and that this conception is just what is meant by idea. It is not some little psychical ent.i.ty or piece of consciousness-stuff, but is _the interpretation of the locally present environment in reference to its absent portion_, that part to which it is referred as another part so as to give a view of a whole. Just how such an idea would differ from one"s plan of action in finding one"s way, I do not know. For one"s plan (if it be really a plan, a method) is a conception of what is given in its hypothetical relations to what is not given, employed as a guide to that act which results in the absent being also given. It is a map constructed with one"s self lost and one"s self found, whether at starting or at home again, as its two limits. If this map in its specific character is not also the only guide to the way home, one"s only plan of action, then I hope I may never be lost. It is the _practical_ facts of being lost and desiring to be found which const.i.tute the limits and the content of the "environment."
Then comes the test of _agreement_ of the idea and the environment.
Supposing the individual stands still and attempts to compare his idea with the reality, with what reality is he to compare it? Not with the presented reality, for _that_ reality is the reality of himself lost; not with the complete reality, for at this stage of proceedings he has only the idea to stand for the complete theory. What kind of comparison is possible or desirable then, save to treat the mental layout of the whole situation as a working hypothesis, as a plan of action, and proceed to _act_ upon it, to use it as a director and controller of one"s divagations instead of stumbling blindly around until one is either exhausted or accidentally gets out? Now suppose one uses the idea--that is to say, the present facts projected into a whole in the light of absent facts--as a guide of action. Suppose, by means of its specifications, one works one"s way along until one comes upon familiar ground--finds one"s self. _Now_, one may say, my idea was right, it was in accord with facts; it agrees with reality. That is, acted upon sincerely, it has led to the desired conclusion; it has, _through action_, worked out the state of things which it contemplated or intended. The agreement, correspondence, is between purpose, plan, and its own execution, fulfillment; between a map of a course constructed for the sake of guiding behavior and the result attained in acting upon the indications of the map. Just how does such agreement differ from success?
III
If we exclude acting upon the idea, no conceivable amount or kind of intellectualistic procedure can confirm or refute an idea, or throw any light upon its validity. How does the non-pragmatic view consider that verification takes place? Does it suppose that we first look a long while at the facts and then a long time at the idea, until by some magical process the degree and kind of their agreement become visible? Unless there is some such conception as this, what conception of agreement is possible except the experimental or practical one? And if it be admitted that verification involves action, how can that action be relevant to the truth of an idea, unless the idea is itself already relevant to action? If by acting in accordance with the experimental definition of facts, viz., as obstacles and conditions, and the experimental definition of the end or intent, viz., as plan and method of action, a harmonized situation effectually presents itself, we have the adequate and the only conceivable verification of the intellectual factors. If the action indicated be carried out and the disordered or disturbed situation persists, then we have not merely confuted the tentative positions of intelligence, but we have in the very process of acting introduced new data and eliminated some of the old ones, and thus afforded an opportunity for the resurvey of the facts and the revision of the plan of action. By acting faithfully upon an inadequate reflective presentation, we have at least secured the elements for its improvement. This, of course, gives no absolute guaranty that the reflection will at any time be so performed as to prove its validity in fact. But the self-rectification of intellectual content through acting upon it in good faith is the "absolute" of knowledge, loyalty to which is the religion of intellect.
The intellectual definition or delimitation a.s.signed to the "given" is thus as tentative and experimental as that ascribed to the idea. In form both are categorical, and in content both are hypothetical. Facts really exist just as facts, and meanings exist as meanings. One is no more superfluous, more subjective, or less necessitated than the other. In and of themselves as existences both are equally realistic and compulsive. But on the basis of existence, there is no element in either which may be strictly described as intellectual or cognitional.
There is only a practical situation in its brute and unrationalized form. What is uncertain about the facts as given at any moment is whether the right exclusions and selections have been made. Since that is a question which can be decided finally only by the experimental issue, this ascription of character is itself tentative and experimental. If it works, the characterization and delineation are found to be proper ones; but every admission prior to inquiry, of unquestioned, categorical, rigid objectivity, compromises the probability that it will work. The character a.s.signed to the datum must be taken as hypothetically as possible in order to preserve the elasticity needed for easy and prompt reconsideration. Any other procedure virtually insists that all facts and details anywhere happening to exist and happening to present themselves (all being equally real) must all be given equal status and equal weight, and that their outer ramifications and internal complexities must be indefinitely followed up. The worthlessness of this sheer acc.u.mulation of realities, its total irrelevancy, the lack of any way of judging the significance of the acc.u.mulations, are good proofs of the fallacy of any theory which ascribes objective logical content to facts wholly apart from the needs and possibilities of a situation.
The more stubbornly one maintains the _full_ reality of either his facts or his ideas, just as they stand, the more accidental is the discovery of relevantly significant facts and of valid ideas--the more accidental, the less rational, is the issue of the knowledge situation. Due progress is reasonably probable in just the degree in which the meaning, categorical in its existing imperativeness, and the fact, equally categorical in its brute coerciveness, are a.s.signed only a provisional and tentative nature with reference to control of the situation. That this surrender of a rigid and final character for the content of knowledge on the sides both of fact and of meaning, in favor of experimental and functioning estimations, is precisely the change which has marked the development of modern from mediaeval and Greek science, seems undoubted. To learn the lesson one has only to contrast the rigidity of phenomena and conceptions in Greek thought (Platonic ideas, Aristotelian forms) with the modern experimental selection and determining of facts and experimental employment of hypotheses. The former have ceased to be ultimate realities of a nondescript sort and have become provisional data; the latter have ceased to be eternal meanings and have become working theories. The fruitful application of mathematics and the evolution of a technique of experimental inquiry have coincided with this change. That realities exist independently of their use as intellectual data, and that meanings exist apart from their utilization as hypotheses, are the permanent truths of Greek realism as against the exaggerated subjectivism of modern philosophy; but the conception that this existence is to be defined in the same way as are contents of knowledge, so that perfect being is object of perfect knowledge and imperfect being object of imperfect knowledge, is the fallacy which Greek thought projected into modern. Science has advanced in its methods in just the degree in which it has ceased to a.s.sume that prior realities and prior meanings retain fixedly and finally, when entering into reflective situations, the characters they had prior to this entrance, and in which it has realized that their very presence within the knowledge situation signifies that they have to be redefined and revalued from the standpoint of the new situation.
IV
This conception does not, however, commit us to the view that there is any conscious situation which is totally non-reflective. It may be true that any experience which can properly be termed such comprises something which is _meant_ over and against what is given or there.
But there are many situations into which the rational factor--the mutual distinction and mutual reference of fact and meaning--enters only incidentally and is slurred, not accentuated. Many disturbances are relatively trivial and induce only a slight and superficial redefinition of contents. This pa.s.sing tension of facts against meaning may suffice to call up and carry a wide range of meaningful facts which are quite irrelevant to the intellectual problem. Such is the case where the individual is finding his way through any field which is upon the whole familiar, and which, accordingly, requires only an occasional resurvey and revaluation at moments of slight perplexity. We may call these situations, if we will, knowledge situations (for the reflective function characteristic of knowledge is present), but so denominating them does not do away with their sharp difference from those situations in which the critical qualification of facts and definition of meanings const.i.tute the main business. To speak of the pa.s.sing attention which a traveler has occasionally to give to the indications of his proper path in a fairly familiar and beaten highway as knowledge, in just the same sense in which the deliberate inquiry of a mathematician or a chemist or a logician is knowledge, is as confusing to the real issue involved as would be the denial to it of _any_ reflective factor. If, then, one bears in mind these two considerations--(1) the unique problem and purpose of every reflective situation, and (2) the difference as to range and thoroughness of logical function in different types of reflective situations--one need have no difficulty with the doctrine that the great obstacle in the development of scientific knowing is that facts and meanings enter such situations with stubborn and alien characteristics imported from other situations.
This affords an opportunity to speak again of the logical problem to which reference and promise of return were made earlier in this paper.
Facts may be regarded as existing qualitatively and in certain spatial and temporal relations; when there is knowledge another relation is added, that of one thing meaning or signifying another. Water exists, for example, as water, in a certain place, in a certain temporal sequence. But it may signify the quenching of thirst; and this signification-relation const.i.tutes knowledge.[57] This statement may be taken in a way congruous with the account developed in this paper.
But it may also be taken in another sense, consideration of which will serve to enforce the point regarding the tentative nature of the characterization of the given, as distinct from the intended and absent. Water means quenching thirst; it is drunk, and death follows.
It was not water, but a poison which "looked like" water. Or it is drunk, and is water, but does not quench thirst, for the drinker is in an abnormal condition and drinking water only intensifies the thirst.
Or it is drunk and quenches thirst; but it also brings on typhoid fever, being not merely water, but water plus germs. Now all these events demonstrate that error may appertain quite as much to the characterization of existing things, suggesting or suggested, as to the suggestion _qua_ suggestion. There is no ground for giving the "things" any superior reality. In these cases, indeed, it may fairly be said that the mistake is made because qualitative thing and suggested or meaning-relation were _not_ discriminated. The "signifying" force was regarded as a part of the direct quality of the given fact, quite as much as its color, liquidity, etc.; it is only in another situation that it is discriminated as a relation instead of being regarded as an element.
It is quite as true to say that a thing is called water because it suggests thirst-quenching as to say that it suggests thirst-quenching because it is characterized as water. _The knowledge function becomes prominent or dominant in the degree in which there is a conscious discrimination between the fact-relations and the meaning-relations._ And this inevitably means that the "water" ceases to be _surely_ water, just as it becomes doubtful or hypothetical whether this thing, whatever it is, really means thirst-quenching. If it really means thirst-quenching, it is water; so far as it may not mean it, it perhaps is not water. It is now just as much a question _what_ this _is_ as what it means. Whatever will resolve one question will resolve the other. In just the degree, then, in which an existence or thing gets intellectualized force or function, it becomes a fragmentary and dubious thing, to be circ.u.mscribed and described for the sake of operating as _sign_, or clue of a _future_ reality to be realized through action. Only as "reality" is reduced to a sign, and questions of its nature as sign are considered, does it get intellectual or cognitional status. The bearing of this upon the question of practical character of the distinctions of fact and idea is obvious. No one, I take it, would deny that action of some sort _does_ follow upon judgment; no one would deny that this action _does_ somehow serve to test the value of the intellectual operations upon which it follows.
But if this subsequent action is _merely_ subsequent, if the intellectual categories, operations, and distinctions are complete in themselves, without inherent reference to it, what guaranty is there that they pa.s.s into relevant action, and by what miracle does the action manage to test the worth of the idea? But if the intellectual identification and description of the thing are as tentative and instrumental as is the ascription of significance, then the exigencies of the active situation are operative in all the categories of the knowledge situation. Action is not a more or less accidental appendage or afterthought, but is undergoing development and giving direction in the entire knowledge function.
In conclusion, I remark that the ease with which the practical character of these fundamental logical categories, fact, meaning, and agreement, may be overlooked or denied is due to the organic way in which practical import is incarnate in them. It can be overlooked because it is so involved in the terms themselves that it is a.s.sumed at every turn. The pragmatist is in the position of one who is charged with denying the existence of something because, in pointing out a certain fundamental feature of it, he puts it in a strange light. Such confusion always occurs when the familiar is brought to definition.
The difficulties are more psychological--difficulties of orientation and mental adjustment--than logical, and in the long run will be done away with by our getting used to the different viewpoint, rather than by argument.
FOOTNOTES:
[52] _Studies in Logical Theory_, University of Chicago Press, 1903.
[53] Mill"s doctrine of the ambiguity of the copula (_Logic_, Book I, chap. IV, -- 1) is an instance of one typical way of evading the problem. After insisting with proper force and clearness upon the objective character of our intellectual beliefs and propositions, viz., that when we say fire causes heat we mean actual phenomena, not our ideas of fire and heat (Book I, chap. II and chap. XI, -- 1, and chap. V, -- 1), he thinks to dispose of the whole problem of the "is"
in judgment by saying that it is only a sign of affirmation (chap. I, -- 2, and chap. IV, -- 1). Of course it is. But unless the affirmation (the sign of thought) "agrees" or "corresponds with" the relations of the phenomena, what becomes of the doctrine of the objective import of propositions? How otherwise shall we maintain with Mill (and with common-sense and science) the difference between a.s.serting "a fact of external nature" and "a fact in my mental history"?
[54] _Studies in Philosophy and Psychology_, article by Woodbridge on "The Problem of Consciousness," especially pp. 159-60.
[55] In other words, "ideas" is a term capable of a.s.suming any definition which is logically appropriate--say, meaning. It need not have anything to do with the conception of little subjective ent.i.ties or psychical stuffs.
[56] Of course, the monistic epistemologies have an advantage in the statement of the problem over the dualistic--they do not state it in terms which presuppose the impossibility of the solution.
[57] This view was originally advanced in the discussion of quite another problem than the one here discussed, viz., the problem of consciousness; and it may not be quite just to dissever it from that context. But as a formula for knowledge it has enough similarity with the one brought out in this paper to suggest further treatment; it is not intended that the results reached here shall apply to the problem of consciousness as such.
IX
NAVE REALISM VS. PRESENTATIVE REALISM[58]
I
In spite of the elucidations of contemporary realists, a number of idealists continue to adduce in behalf of idealism certain facts having an obvious physical nature and explanation. The visible convergence of the railway tracks, for example, is cited as evidence that what is seen is a mental "content." Yet this convergence follows from the physical properties of light and a lens, and is physically demonstrated in a camera. Is the photograph, then, to be conceived as a psychical somewhat? That the time of the visibility of a light does not coincide with the time at which a distant body emitted the light is employed to support a similar idealistic conclusion, in spite of the fact that the exact difference in time may be deduced from a physical property of light--its rate. The dislocation in s.p.a.ce of the light seen and the astronomical star is used as evidence of the mental nature of the former, though the exact angular difference is a matter of simple computation from purely physical data. The doubling of images of, say, the finger when the eyeball is pressed, is frequently proffered as a clincher. Yet it is a simple matter to take any body that reflects light, and by a suitable arrangement of lenses to produce not only two but many images, projected into s.p.a.ce. If the fact that under definite _physical_ conditions (misplacement of lenses), a finger yields two images proves the psychical character of the latter, then the fact that under certain conditions a sounding body yields one or more echoes is, by parity of reasoning, proof that the echo is made of mental stuff.[59]
If, once more, the differences in form and color of a table to different observers, occupying different physical positions, is proof that what each sees is a psychical, private, isolated somewhat, then the fact that one and the same physical body has different effects upon, or relations with, different physical media is proof of the mental nature of these effects. Take a lump of wax and subject it to the same heat, located at different positions; now the wax is solid, now liquid--it might even be gaseous. How "psychical" these phenomena!
It almost seems as if the transformation of the physical into the mental in the cases cited exemplifies an interesting psychological phenomenon. In each case the beginning is with a real and physical existence. Taking "the real object," the astronomical star, on the basis of its physical reality, the idealist concludes to a psychical object, radically different! Taking the _single_ object, the finger, from the premise of its real singleness, he concludes to a double mental content, which then takes the place of the original single thing! Taking one-and-the-same-object, the table, presenting _its_ different surfaces and reflections of light to different real organisms, he eliminates the one-table-in-its-different-relations in behalf of a multiplicity of totally separate psychical tables! The logic reminds us of the story of the countryman who, after gazing at the giraffe, remarked, "There ain"t no such animal." It almost seems, I repeat, as if this self-contradiction in the argument creates in some minds the impression that the object--not the argument--is undergoing the extraordinary reversal of form.
However this may be, the problem indicated in the foregoing cases is simply the good old problem of the many in one, or, less cryptically, the problem of the maintenance of a continuity of process throughout differences. I do not pretend that this situation, though the most familiar thing in life, is wholly without difficulties. But its difficulty is not one of epistemology, that is, of the relation of known to a knower; to take it as such, and then to use it as proof of the psychical nature of a final term, is also to prove that the trail the rocket stick leaves behind is psychical, or that the flower which comes in a continuity of process from a seed is mental.
II
Contemporary realists have so frequently and clearly expounded the physical explanation of such cases as have been cited that one is at a loss as to why idealists go on repeating the cases without even alluding to the realistic explanation. One is moved to wonder whether this neglect is just one of those circ.u.mstances which persistently dog philosophical discussions, or whether something in the realistic position gives ground (from at least an _ad hominem_ point of view) for the neglect. There is a reason for adopting the latter alternative. Many realists, in offering the type of explanation adduced above, have treated the cases of seen light, doubled imagery, as perception in a way that ascribes to perception an inherent cognitive status. They have treated the perceptions as _cases of knowledge_, instead of as simply natural events having, in themselves (apart from a _use_ that may be made of them), no more knowledge status or worth than, say, a shower or a fever. What I intend to show is that if "perceptions" are regarded as cases of knowledge, the gate is opened to the idealistic interpretation. The physical explanation holds of them as long as they are regarded simply as natural events--a doctrine I shall call nave realism; it does not hold of them considered as cases of knowledge--the view I call presentative realism.
The idealists attribute to the realists the doctrine that "the perceived object is the real object." Please note the wording; it a.s.sumes that there is _the_ real object, something which stands in a contrasting relation with objects not real or else less real. Since it is easily demonstrable that there is a numerical duplicity between the astronomical star and its effect of visible light, between the single finger and the doubled images, the latter evidently, when the former is dubbed "_the_" real object, stands in disparaging contrast to its reality. _If_ it is a case of knowledge, the knowledge refers to the star; and yet not the star, but something more or less unreal (that is, if the star be "the" real object), is known.
Consider how simply the matter stands in what I have called nave realism. The astronomical star is _a_ real object, but not "the" real object; the visible light is another real object, found, when knowledge supervenes, to be an occurrence standing in a process continuous with the star. Since the seen light is an event within a continuous process, there is no point of view from which its "reality" contrasts with that of the star.
But suppose that the realist accepts the traditionary psychology according to which every event in the way of a perception is also a case of knowing something. Is the way out now so simple? In the case of the doubled fingers or the seen light, the thing known in perception contrasts with the physical source and cause of the knowledge. There _is_ a numerical duplicity. Moreover the thing known by perception is by this hypothesis in relation to a knower, while the physical cause is not. Is not the most plausible account of the difference between the physical cause of the perceptive knowledge and what the latter presents precisely this latter difference--namely, presentation to a knower? If perception is a case of knowing, it must be a case of knowing the star; but since the "real" star is not known in the perception, the knowledge relation must somehow have changed the "object" into a "content." Thus when the realist conceives the perceptual occurrence as an intrinsic case of knowledge or of presentation to a mind or knower, he lets the nose of the idealist camel into the tent. He has then no great cause for surprise when the camel comes in--and devours the tent.
Perhaps it will seem as if in this last paragraph I had gone back on what I said earlier regarding the physical explanation of the difference between the visible light and the astronomical star. On the contrary, my point is that this explanation, though wholly adequate as long as we conceive the perception to be itself simply a natural event, is not at all available when we conceive it to be an attempt at knowing its cause. In the former case, we are dealing with a relation between natural events. In the latter case, we are dealing with the difference between an object as a cause of knowledge and an object as known, and hence in relation to mind. By the "method of difference" the sole explanation of the difference between the two objects is then the absence or presence of relation to a knower.
In the case of the seen light,[60] reference to the velocity of light is quite adequate to account for its time and s.p.a.ce differences from the star. But viewed as a case of what is known (on the supposition that perception is knowing), reference to it only increases the contrast between the real object and the object known in perception.
For, being just as much a part of the object that causes the perception as is the star itself, it (the velocity of light) _ought_ logically to be part of what is known in the perception, while it is not. Since the velocity of light is a const.i.tuent element in the star, it should be known in the perception; since it is not so known, reference to it only increases the discrepancy between the object of the perception--the seen light--and the real, astronomical star. The same is true of any physical condition that might be referred to: _The very things that, from the standpoint of perception as a natural event, are conditions that account for its happening are, from the standpoint of perception as a case of knowledge, part of the object which, if knowledge is to be valid, ought to be known, but is not._