When assured, such a simple datum is for the sake of guarding the act of inference. Color may mean a lot of things; any red may mean a lot of things; such things are ambiguous; they afford unreliable evidence or signs. To get the color down to the last touch of possible discrimination is to limit its range of testimony; ideally, it is to secure a voice which says but one thing and says that unmistakably. Its simplicity is not identical with isolation, but with specified relationship. Thus the hard "facts," the brute data, the simple qualities or ideas, the sense elements of traditional and of contemporary logic, get placed and identified within the art of controlling inference. The allied terms "self-evident," "sensory truths," "simple apprehensions" have their meanings unambiguously determined in this same context; while apart from it they are the source of all kinds of error. They are no longer notions to conjure with. They express the last results attainable by present physical methods of discriminative analysis employed in the search for dependable data for inference. Improve the physical means of experimentation, improve the microscope or the registering apparatus or the chemical reagent, and they may be replaced tomorrow by new, simple apprehensions of simple and ultimate data.
b) Natural or spontaneous inference depends very largely upon the habits of the individual in whom inferring takes place. These habits depend in turn very largely upon the customs of the social group in which he has been brought up. An eclipse suggests very different things according to the rites, ceremonies, legends, traditions, etc., of the group to which the spectator belongs. The average layman in a civilized group may have no more personal science than an Australian Bushman, but the legends which determine his reactions are different. His inference is better, neither because of superior intellectual capacity, nor because of more careful personal methods of knowing, but because his instruction has been superior. The instruction of a scientific inquirer in the best scientific knowledge of his day is just as much a part of the control (or art) of inference as is the technique of observational analysis which he uses. As the bulk of prior ascertainments increases, the tendency is to identify this stock of learning, this store of achieved truth, with knowledge. There is no objection to this identification save as it leads the logician or epistemologist to ignore that which made it "knowledge" (that which gives it a right to the title), and as a consequence to fall into two errors: one, overlooking its function in the guidance and handling of future inferences; the other, confusing the mere act of reference to what is known (known so far as it has accrued from prior tested inquiries) with knowing. To remind myself of what is known as to the topic with which I am dealing is an indispensable performance, but to call this reminder "knowing" (as the presentative realist usually does) is to confuse a psychological event with a logical achievement. It is from misconception of this act of reminding one's self of what is known, as a check in some actual inquiry, that arise most of the fallacies about simple acquaintance, mere apprehension, etc.—the fallacies which eliminate inquiry and inferring from knowledge.
c) The art of inference gives rise to specific features characterizing the inferred thing. The natural man reacts to the suggested thing as he would to something present. That is, he tends to accept it uncritically. The man called up by the footprint on the sand is just as real a man as the footprint is a real footprint. It is a man, not the idea of a man, which is indicated. What a thing means is another thing; it doesn't mean a meaning. The only difference is that the thing indicated is farther off, or more concealed, and hence (probably) more mysterious, more powerful and awesome, on that account. The man indicated to Crusoe by the footprints was like a man of menacing powers seen at a distance through a telescope. Things naturally inferred are accepted, in other words, by the natural man on altogether too realistic a basis for adequate control; they impose themselves too directly and irretrievably. There are no alternatives save either acceptance or rejection in toto. What is needed for control is some device by which they can be treated for just what they are, namely, inferred objects which, however assured as objects of prior experiences, are uncertain as to their existence in connection with the object from which present inference sets out. While more careful inspection of the given object—to see if it be really a footprint, how fresh, etc.—may do much for safe-guarding inference; and while forays into whatever else is known may help, there is still need for something else. We need some method of freely examining and handling the object in its status as an inferred object. This means some way of detaching it, as it were, from the particular act of inference in which it presents itself. Without some such detachment, Crusoe can never get into a free and effective relation with the man indicated by the footprint. He can only, so to speak, go on repeating, with continuously increasing fright, "There's a man about, there's a man about." The "man" needs to be treated, not as man, but as something having a merely inferred and hence potential status; as a meaning or thought, or "idea." There is a great difference between meaning and a meaning. Meaning is simply a function of the situation: this thing means that thing: meaning is this relationship. A meaning is something quite different; it is not a function, but a specific entity, a peculiar thing, namely the man as suggested.
Words are the great instrument of translating a relation of inference existing between two things into a new kind of thing which can be operated with on its own account; the term of discourse or reflection is the solution of the requirement for greater flexibility and liberation. Let me repeat: Crusoe's inquiry can play freely around and about the man inferred from the footprint only as he can, so to say, get away from the immediate suggestive force of the footprint. As it originally stands, the man suggested is on the same coercive level as the suggestive footprint. They are related, tied together. But a gesture, a sound, may be used as a substitute for the thing inferred. It exists independently of the footprint and may therefore be thought about and ideally experimented with irrespective of the footprint. It at once preserves the meaning-force of the situation and detaches it from the immediacy of the situation. It is a meaning, an idea.
Here we have, I submit, the explanation of notions, forms, essences, terms, subsistences, ideas, meanings, etc. They are surrogates of the objects of inference of such a character that they may be elaborated and manipulated exactly as primary things may be, so far as inference is concerned. They can be brought into relation with one another, quite irrespective of the things which originally suggested them. Without such free play reflective inquiry is mockery, and control of inference an impossibility. When a speck of light suggests to the astronomer a comet, he would have nothing to do but either to accept the inferred object as a real one, or to reject it as a mere fancy unless he could treat "comet" for the time being not as a thing at all, but as a meaning, a conception; a meaning having, moreover, by connection with other meanings, implications—meanings consequent from it. Unless a meaning is an inferred object, detached and fixed as a term capable of independent development, what sort of a ghostly Being is it? Except on the basis stated, what is the transition from the function of meaning to a meaning as an entity in reasoning? And, once more, unless there is such a transition, is reasoning possible?
Cats have claws and teeth and fur. They do not have implications. No physical thing has implications. The term "cat" has implications. How can this difference be explained? On the ground that we cannot use the "cat" object inferred from given indications in such a way as will test the inference and make it fruitful, helpful, unless we can detach it from its existential dependence upon the particular things which suggest it. We need to know what a cat would be if it were there; what other things would also be indicated if the cat is really indicated. We therefore create a new object: we take something to stand for the cat-in-its-status-as-inferred in contrast with the cat as a live thing. A sound or a visible mark is the ordinary mechanism for producing such a new object. Whatever the physical means employed, we now have a new object; a term, a meaning, a notion, an essence, a form or species, according to the terminology which may be in vogue. It is as much a specific existence as any sound or mark is. But it is a mark which notes, concentrates, and records an outcome of an inference which is not yet accepted and affirmed. That is to say, it designates an object which is not yet to be reacted to as one reacts to the given stimulus, but which is an object of further examination and inquiry, a medium of a postponed conclusion and of investigation continued till better grounds for affirming an object (making a definite, unified response) are given. A term is an object so far as that object is undergoing shaping in a directed act of inquiry. It may be called a possible object or a hypothetical object. Such objects do not walk or bite or scratch, but they are nevertheless actually present as the vital agencies of reflection. If we but forget where they live and operate—within the event of controlled inference—we have on our hands all the mysteries of the double world of existence and essence, particular and universal, thing and idea, ordinary life and science. For the world of science, especially of mathematical science, is the world of considerations which have approved themselves to be effectively regulative of the operations of inference. It is easier to wash with ordinary water than with H2O, and there is a marked difference between falling off a building and ½gt2. But H2O and ½gt2 are as potent for the distinctive act of inference—as genuine and distinctive an act as washing the hands or rolling down hill—as ordinary water and falling are impotent.
Scientific men can handle these things-of-inference precisely as the blacksmith handles his tools. They are not thoughts as they are ordinarily used, not even in the logical sense of thought. They are rather things whose manipulation (as the blacksmith manipulates his tools) yield knowledge—or methods of knowledge—with a minimum of recourse to thinking and a maximum of efficiency. When one considers the importance of the enterprise of knowledge, it is not surprising that appropriate tools have been devised for carrying it on, and that these tools have no prototypes in pre-existent materials. They are real objects, but they are just the real objects which they are and not some other objects.
THEORY AND PRACTICE
Our last paragraphs have touched upon the nature of science. They contain, by way of intimation, an explanation of the distance which lies between the things of daily intercourse and the terms of science. Controlled inference is science, and science is, accordingly, a highly specialized industry. It is such a specialized mode of practice that it does not appear to be a mode of practice at all. This high specialization is part of the reason for the current antithesis of theory and practice, knowledge and conduct, the other part being the survival of the ancient conception of knowledge as intuitive and dialectical—the conception which is set forth in the Aristotelian logic.
Starting from the hypothesis that the art of controlled inference requires for its efficient exercise specially adapted entities, it follows that the various sciences are the various forms which the industry of controlled inquiry assumes. It follows that the conceptions and formulations of the sciences—physical and mathematical—concern things which have been reshaped in view of the exigencies of regulated and fertile inference. To get things into the estate where such inference is practicable, many qualities of the water and air, cats and dogs, stones and stars, of daily intercourse with the world have been dropped or depressed. Much that was trivial or remote has been elevated and exaggerated. Neither the omissions nor the accentuations are arbitrary. They are purposeful. They represent the changes in the things of ordinary life which are needed to safeguard the important business of inference.