Sense data

“ Thus it is the fact that different people have similar sense-data, and that one person in a given place at different times has similar sense-data, which makes us suppose that over and above the sense-data there is a permanent public object which underlies or causes the sense-data of various people and various times. ”

“ Men of science, for the most part, are willing to condemn immediate data as “merely subjective,” while yet maintaining the truth of the physics inferred from those data. But such an attitude, though it may be capable of justification, obviously stands in need of it; and the only justification possible must be one which exhibits matter as a logical construction from sense-data—unless, indeed, there were some wholly a priori principle by which unknown entities could be inferred from such as are known. ”

“ We may succeed in actually defining the objects of physics as functions of sense-data. Just in so far as physics leads to expectations, this must be possible, since we can only expect what can be experienced. And in so far as the physical state of affairs is inferred from sense-data, it must be capable of expression as a function of sense-data. ”

“ I propose to assert that sense-data are physical, while yet maintaining that they probably never persist unchanged after ceasing to be data. The view that they do not persist is often thought, quite erroneously in my opinion, to imply that they are mental ”

“ A complete application of the method which substitutes constructions for inferences would exhibit matter wholly in terms of sense-data, and even, we may add, of the sense-data of a single person, since the sense-data of others cannot be known without some element of inference. ”

“ I have maintained that sensations are data for psychology and physics equally, while images, which may be in some sense exclusively psychological data, can only be distinguished from sensations by their correlations, not by what they are in themselves. It is now necessary, however, to examine the notion of a "datum," and to obtain, if possible, a definition of this notion.
The notion of "data" is familiar throughout science, and is usually treated by men of science as though it were perfectly clear. Psychologists, on the other hand, find great difficulty in the conception. ”

“ There is in fact a certain regularity or conformity to law about the occurrence of sense-data, but the sense-data that occur at one time are often causally connected with those that occur at quite other times, and not, or at least not very closely, with those that occur at neighbouring times. ”

“ The view that sense-data are mental is derived, no doubt, in part from their physiological subjectivity, but in part also from a failure to distinguish between sense-data and "sensations." By a sensation I mean the fact consisting in the subject's awareness of the sense-datum. Thus a sensation is a complex of which the subject is a constituent and which therefore is mental. ”

“ Since the usual correlations and connections become part of our unreflective expectations, and even seem, except to the psychologist, to form part of our data, it comes to be thought, mistakenly, that in such cases the data are unreal, whereas they are merely the causes of false inferences. The fact that correlations and connections of unusual kinds occur adds to the difficulty of inferring things from sense and of expressing physics in terms of sense-data. ”

“ The reason why the projected sense-data are in general used as symbol, is that they are handy, definite, and manageable. We can see, or not see, as we like: we can hear, or not hear. There are limits to this handiness of the sense-data: but they are emphatically the manageable elements in our perceptions of the world. ”

“ It is only when we ask how physics can be known that the importance of sense-data re-emerges.
III. SENSIBILIAtop
I shall give the name sensibilia to those objects which have the same metaphysical and physical status as sense-data, without necessarily being data to any mind. Thus the relation of a sensibile to a sense-datum is like that of a man to a husband: a man becomes a husband by entering into the relation of marriage, and similarly a sensibile becomes a sense-datum by entering into the relation of acquaintance. ”

“ But all who regard sense data as apprehensions have on their hands in some form the problem of the seemingly distorting action exercised by the [412] individual knower upon a public or common thing known or believed in. ”

“ If physics is to consist wholly of propositions known to be true, or at least capable of being proved or disproved, the three kinds of hypothetical entities we have just enumerated must all be capable of being exhibited as logical functions of sense-data. ”

“ As data, though entitled to a certain limited respect, they cannot be placed on a level with the facts of sense or the laws of logic. The kind of respect which they deserve seems to me such as to warrant us in hoping, though not too confidently, that the hard data may prove them to be at least probable. Also, if the hard data are found to throw no light whatever upon their truth or falsehood, we are justified, I think, in giving rather more weight to the hypothesis of their truth than to the hypothesis of their falsehood. ”

“ The question whether sense-data are composed of mutually external units is not one which can be decided by empirical evidence. It is often urged that, as a matter of immediate experience, the sensible flux is devoid of divisions, and is falsified by the dissections of the intellect. ”

“ We may say that we know some principle a priori, without the need of empirical verification, e.g. that our sense-data have causes other than themselves, and that something can be known about these causes by inference from their effects. This way has been often adopted by philosophers. It may be necessary to adopt this way to some extent, but in so far as it is adopted physics ceases to be empirical or based upon experiment and observation alone. ”

“ With relation to the unquestionable case of knowledge, the logical or inferential case, perceptions occupy a unique status, one which readily accounts for their being regarded as cases of knowledge, although in themselves they are natural events. (1) They are the sole ultimate data, the sole media, of inference to all natural objects and processes. While we do not, in any intelligible or verifiable sense, know them, we know all things that we do know with or by them. ”

“ Science has, by appeal to various bases, included a multitude of data. Had it not done so, there would be nothing with which to seem to be. Science has, by appeal to various bases, excluded a multitude of data. ”

“ In statistics, it is evident that empirical laws may sometimes be traced; and the tracing them forms an important part of that system of indirect observation on which we must often rely for the data of the Deductive Science. ”

“ Do we find that the quantity of acquirement measures the quantity of insight? Is the amount of cardinal truth reached to be inferred from the mass of collected facts that serve as appliances for reaching it? By no means. Wisdom and information do not vary together. Though there must be data before there can be generalization, yet ungeneralized data, accumulated in excess, are impediments to generalization. When a man's knowledge is not in order, the more of it he has the greater will be his confusion of thought. ”

“ Simple inspection of the data enables us to perceive them; and one inspection is as effective as a million for engendering in us the conviction that between those data that relation must always hold. To change the relation we should have to make the data different. 'The guarantee for the uniformity and adequacy' of the data can only be the mind's own power to fix upon any objective content, and to mean that content as often as it likes. ”

“ It would place us in that position of more advanced knowledge, in which the probabilities, to us, would be different from what they were before; and in estimating these new probabilities we should have to proceed on a totally different set of data, furnished no longer by mere counting of possible suppositions, but by specific knowledge of facts. Such data it should always be our endeavor to obtain; and in all inquiries, unless on subjects equally beyond the range of our means of knowledge and our practical uses, they may be obtained, if not good, at least better than none at all. ”

“ Further, when a proposition which is a datum asserts the existence of something, we say that the something is a datum, as well as the proposition asserting its existence. Thus those objects of whose existence we become certain through perception are said to be data. ”

“ Only where things can be seen by many in a variety of aspects without changing their identity can worldly reality truly and reliably appear.’53 It is also worth noting that the interpretation of data in many parts of scientific practice relies on mediated subjective thinking and interpretation: the data do not speak for themselves. ”

“ We have stated that, strictly speaking, data (as the immediate considerations from which controlled inference proceeds) are not objects but means, instrumentalities, of knowledge: things by which we know rather than things known. It is by the color stain that we know a cellular structure; it is by marks on a page that we know what some man believes ”

“ Thus it happens, that as theories approach to their perfection, a more and more exact determination of data becomes requisite. Deviations from observed fact, which, in a first or approximative verification, may be disregarded as trifling, become important when a high degree of precision is attained. ”

“ On the one hand, the data furnished by experience, and on the other, general and necessary truths, form a connection constituting a positive science, which guides us with perfect security to the cognition of objects not subject to immediate experience. ”

“ Still, there are generally certain surviving data, in place-names, natural features, and so forth, which enable those who can detect them, and make use of them, to piece together something like a connected outline of what we may take, with some degree of probability, as an approximation to what have been actual facts, although lacking, at the time, the chronicler to record them. ”

“ Whether or not we can imagine, or mentally represent, a thing as real, depends upon the question whether our past experience has furnished us the data for such a representation; and our experience is constantly furnishing us new data. ”

“ In the absence of data we must abandon the analytic or scientific method of investigation, and must approach it in the synthetic fashion. In a word, instead of taking known events and deducing from them what has occurred, we must build up a fanciful explanation if it will only be consistent with known events. We can then test this explanation by any fresh facts which may arise. ”

“ And when we deliberately set ourselves to obtain uniformities by taking an average result, derived from comparison of a multitude of subjects, our results are, of course, always mechanical in appearance, because the element of individual purpose and initiative has been excluded by ourselves from our data in the very process of taking the average. ”

“ That is to say, in psychology we use data which can only be obtained when the observer and the observed are the same person, whereas in the other ways of studying Man all our data can be obtained by observing other people. ”

“ It ought to be remarked, that these are, of all others, the conjunctures where observations are most available for the determination of data; for, by the same rule that a small change in the data will, in such cases, produce a great one in the thing to be observed; so, vice versâ, any moderate amount of error, committed in an observation undertaken for ascertaining its value, can produce but a very trifling one in the reverse calculation from which the data come to be determined by observation. ”

“ The object of the Data is to show that when certain things—lines, angles, spaces, ratios, &c.—are given by hypothesis, certain other things are given, that is, are determinable. The book, as we are expressly told, and as we may gather from its contents, was intended for the investigation of problems; and it has been conjectured that Euclid must have extended the method of the Data to the investigation of theorems. ”

“ The method used in positive sciences is not the analysis of primary data. The method of analysis works on extremely simple systems, which can be perceived on image models as well. The method used in positive sciences is to guess a symbolic model, based more or less on the interaction with external reality, and to verify the model. ”

“ If an observer is clever, then, he can use a series of measurements on part of his data-set to ground a guess about a pattern that holds in that data set, and then use that pattern to ground a guess about the values of unmeasured parts of the data set. ”

“ The principles and data are thus both involved in the selecting process, or step of analysis. What the learner really does, therefore, in a deductive lesson [136] is to interpret a new problem by selecting as interpreting ideas the principles and data. The third division, inference, is in reality the third step of our learning process, since the inference is a new experience organized out of the selected principles and data. Moreover, the verification is often found to take the form of ordinary expression. ”

“ Knowledge which is of the highest order in respect of certainty, and which we call exact science, is distinguished from other knowledge by its definitely quantitative previsions.22 It sets out with data, and proceeds by steps which, taken together, enable it to say under what specified conditions a specified relation of phenomena will be found ”