Matthew D. Lund

Of the many sorts of questions that can be asked of a specific piece of reasoning in natural science the following three may be distinguished: 1. Does it follow? That is, are the conclusions so related to the evidence (or premises) that they may be said necessarily to follow from them? This first question is independent of any question of truth or falsity. It is designed strictly in terms of what might be called consistency. 2. Is it true? This usually comes to the question Are the premises true?, or, Are the data correct?, though it must be remembered that true conclusions can follow from false premises. For that reason we must distinguish questions about the truth of an argument from questions about the consistency of the same argument. Ptolemaic astronomy is consistent but false, and there are arguments in modern physics which, though they turn up answers that are true, are nevertheless formally inconsistent. We have had occasion to discuss all this before. But not much has been said about the following question: 3. How is the truth of the premises established?

We have been discussing some of the fundamental features of the classical calculus of probability. The equiprobability of rival events was seen to be a major assumption of the calculus. Moreover, it is an assumption which the pure mathematician need not bother to justify. He need only present his formal system as follows:If all the alternatives are equiprobable, then my system provides the complete machinery for calculating the probability of alternative events occurring.But whether actual alternatives, say in a laboratory experiment, are equiprobable is not for the pure mathematician to say. He is concerned only to work out the consequences of a system based upon that assumption.

Historians of science are more than mere chroniclers. They are not content only to construct a master record of what happened and when—of discoveries, inventions, and scientific personalities, of birthdays and family connections. True, many books on the history of some science read as if the author were designing a kind of periodic table or a calendar or a genealogical tree of the events which have made the science what it is. But this is to history of science at its best as bird watching is to genetic theory.

One thing we noted in the last chapter was how the label “law of nature” is applied to several quite different types of statement. Boyle’s law is a straightforward law of nature. So is Snell’s law. Snell’s law, however, involves a theoretical term—“light ray.” Boyle’s law requires no such term. The laws of motion and of electromagnetics and thermodynamics are laws of nature, too, and they are riddled with theoretical terms, being less like formal summaries of what we observe and more like the axioms of a calculus. Thus, we are versatile in our use of the expression “law of nature.”

Our last chapter concluded with the suggestion that at least some of our laws of nature are the laws of our method of representing nature. The laws of mechanics, thus, are just the laws of the methods by the use of which we represent mechanical phenomena. Or, to put it another way, the laws of mechanics are the laws which relate our mechanical concepts. To this was appended the even more alarming thesis that, all this being so, the laws of mechanics are not facts about the world at all. Laws of nature are not facts about nature. Clearly, this needs support.

The logic of notions like see, observe, witness, notice, data, evidence, and facts has, for my purposes at least, been thoroughly explored. For the next few chapters I should like to see how the morals drawn from our work so far can be applied in cases of actual scientific perplexity. The present chapter, therefore, as well as the two to follow, will be addressed, not to logical exploration (as the previous chapters were), but to the application of the fruits of our study to typical cases of experimental research.

In Chap. 14 I spoke at length about crucial experiments. I argued that crucial experiments are crucial only against the background of a relatively stable set of assumptions, assumptions we are not prepared to abandon lightly. Crucial experiments, therefore, are tests not only of isolated hypotheses but of an hypothesis plus all those assumptions that underlie the enunciation of that hypothesis. The Fresnel, Young, and Foucault experiments were crucial in the controversy over the nature of light only when viewed against the assumption that light must be wavelike or particulate, but at least one or the other and in no case both. So these famous optical experiments were crucial to the question of the nature of light and crucial also to underlying hypotheses, including this one. What are called “crucial experiments” are only the surface ripples manifested by deep and complex crosscurrents in scientific thinking. They certainly constitute much more than the superficially simple decisions they are sometimes represented as exhibiting.

I tried in the last chapter slightly to unfix your views about what we ordinarily call the facts. By tinkering with the ordinary language in which we so often make statements of fact, I hoped to suggest that the whole character of what we refer to as facts might alter significantly with each change in the fact-stating language. And, of course, the obvious moral of this applies with equal force to the technical and mathematical languages of systematic science; the logical character of the notation and syntax we use to express ourselves is not an inconsiderable factor in the formation of our conception of the physical world. This point has been sharply made in modern physics—especially in elementary particle theory, where, perhaps, all of the limitations placed on our conceptions of what the microphysical world is like are really limitations arising out of the linguistic features of the formal languages available. This is certainly the case with the infamous and much misunderstood uncertainty relations, for example: Though this feature of quantum theory is very often announced as constituting a limit to the possibility of observation within microphysics, the statement is true in a rather different sense than is often supposed. There have never been any experiments or any observations pertinent to the establishment of the uncertainty relations. Nor could there be such. These relations are a logical consequence of the language of quantum physics, a language the utility of which is now very well established by experiment. Or, to put it another way, the uncertainty relations would result from any attempt to synchronize the symbolic description of a wave process with the symbolic description of a particle’s state. All of the several quantum languages agree in this, though they put it in different ways. Some will treat it as a logical effect of the wave-packet conception of an elementary particle; others will talk of non-commutativity of operators. It all comes to the same thing. There is a logical-linguistic obstacle in the way of our describing with precision the total state of an elementary particle. So, of course, if this is a logical limit to description, it is ipso facto a limit on observation. Observation of the impossible is impossible.

We have been dealing with the concept of “seeing as.…” It has been argued that in most of the cases where we speak of what we see, as when we see boxes, ducks, rabbits, bears, bicycles, and x-ray tubes, we are speaking of having visual impressions which we see as boxes, ducks, rabbits, etc. This seeing as is a central component of what we ordinarily call “seeing.” Several cases were noted of people having roughly the same retinal reactions to a visual stimulus X, and perhaps having the same visual impressions, or sense-data, of it as well, but where the parties concerned did not see X in the same way. One sees X as a Y, the other sees it as a Z, etc. And besides considering slightly bizarre examples of this, things like reversible figures and shifting-aspect figures, we saw that in certain important respects the seeing of airfoils, x-ray tubes, bicycles—indeed, the seeing of most of our familiar material objects—consists in part of this element I have been calling “seeing as …” When our seeing of physical objects lacks this “seeing as …” quality, e.g., in the oculist’s office or when in research we encounter a visual phenomenon wholly new to our experience, we are up against the unusual cases, the non-typical cases. That is my contention. These cases are outstanding and important only when contrasted with our more usual varieties of seeing things. The “phenomenal” description of what the research microscopist sees is only instrumental to his goal of one day describing what is before him on the slide in physical object terms, in terms of what the thing before his eyes is seen as.

We have discussed at length the concepts of seeing and observing. The intellectual and linguistic character of seeing was remarked in such a way that we could at least detect some justice in the assertion that our two astronomers, the thirteenth century man and the twentieth century man, do not see the same thing in the east at dawn. In just this way two doctors may not see the same thing when looking at an x-ray photograph. Nor will two microbiologists necessarily see the same thing when looking at a protozoon, particularly if one calls it a one-celled organism and the other calls it a non-celled organism.

It was clear in the preceding chapter that if one interpreted “seeing the sun” as “having a normal retinal reaction to the sun,” then our thirteenth and twentieth century astronomers do indeed see the same thing. But we noted a good many objections to interpreting seeing in this way. We found many cases where it could be established that a person’s retinal reaction to the sun was altogether normal, and yet the person would not be said to be seeing the sun—because of distraction, hypnosis, intoxication, somnambulism, paresis, etc.

In the last chapter we encountered four figures—a cube, a rhomboid, a staircase, and a tunnel—all of which displayed the phenomenon of reversible perspective. We also considered two drawings which, besides showing some variability in perspective, were marked by shifts in organization, or in aspect. These were called the “duck-rabbit” and the “wife-mother-in-law” respectively. In each case the question was asked, “Do we all see the same thing?” For there was no question here of a differing retinal reaction. The stimulus pattern is roughly the same for all onlookers. Nor is it easy to see how we could defensibly speak of our different reactions to these figures as being accompanied by different visual sensations, i.e., different sense-data. And yet, undeniably, different reports are forthcoming when we ask of people viewing these figures, “What do you see?”

In 1823, F.W. Bessel published a startling conclusion: ‘involuntary constant differences’ mark out the recorded astronomical transit times of distinct observers. Bessel’s discovery eventually led to the institutionalization of the ‘personal equation’ for astrometry and spurred psychological investigations into the processes of visual perception. Bessel’s discovery revealed that the epistemic terrain of astrometry was more unpredictable than had been previously thought. Yet the solution to these worries was not a rigorous theory of the observer, but rather a set of cautionary practices in data recording. This paper investigates the reasoning process Bessel used to discover involuntary constant differences and asks whether the apparent perceptual relativity he had discovered constituted a threat to data integrity. Bessel’s solution was epistemically responsible because it treated individual observational differences as a type of potential error that was avoided by preventing mixed observations. Additionally, error was not primarily viewed as a mismatch with reality, but rather as endemic to observational data, which kept the focus on practical matters rather than ontological ones.

David Kinnebrook is remembered as the assistant to the Astronomer Royal dismissed in 1796 for marking stellar transits too slowly. Kinnebrook’s firing is commonly listed as the origin point for the personal equation and empirical psychology. Historians have viewed Kinnebrook as a slightly misused, although mute, party in the affair, drawing their accounts from Nevil Maskelyne’s published account of the dismissal. Kinnebrook’s letters, which resurfaced in 1985, detail a monthslong dispute with Maskelyne concerning observational disagreements. The letters provide an account of observational practice and individual differences in marking transits; they also detail Maskelyne’s failure to recognize an epistemic problem. Kinnebrook’s letters show that the problem of individual differences was known to Maskelyne as well as several of his contemporaries. Evidence from the letters shows that Maskelyne passed off six weeks of observations collected by his disgraced assistant as his own. The letters also state that Maskelyne had substantial personal observational differences with previous assistants. While Bessel later conjectured that Kinnebrook was under pressure to speed up his observations, Kinnebrook’s letters confirm that conjecture and reveal that Kinnebrook had a deeper comprehension of the epistemological problems of observation than has been recognized. Kinnebrook’s recognition of personal differences in marking stellar transits is a significant moment in the prehistory of the personal equation.

Norwood Russell Hanson was one of the most important philosophers of science of the post-war period. Hanson brought Wittgensteinian ordinary language philosophy to bear on the concepts of science, and his treatments of observation, discovery, and the theory-ladenness of scientific facts remain central to the philosophy of science. Additionally, Hanson was one of philosophy’s great personalities, and his sense of humor and charm come through fully in the pages of Perception and Discovery. Perception and Discovery, originally published in 1969, is Hanson’s posthumous textbook in philosophy of science. The book focuses on the indispensable role philosophy plays in scientific thinking. Perception and Discovery features Hanson’s most complete and mature account of theory-laden observation, a discussion of conceptual and logical boundaries, and a detailed treatment of the epistemological features of scientific research and scientific reasoning. This book is of interest to scholars of philosophy of science, particularly those concerned with Hanson’s thought and the development of the discipline in the middle of the 20th century. However, even fifty years after Hanson’s early death, Perception and Discovery still has a great deal to offer all readers interested in science.

Fifty years have passed since Norwood Russell Hanson's unexpected death, yet he remains an important voice in philosophy of science. This book is a revised and expanded edition of a collection of Hanson's essays originally published in 1971, edited by Stephen Toulmin and Harry Woolf. The new volume features a comprehensive introduction by Matthew Lund (Rowan University) and two new essays. The first is "Observation and Explanation: A Guide to Philosophy of Science", originally published as a posthumous book by Harper and Row. This essay, written near the end of Hanson’s life, represents his mature philosophy of science. The second new addition, Hanson's essay "The Trial of Galileo", is something of a "lost" work – it was only published in a small run collection on famous trials and was left out of the published lists of Hanson’s works. Ever the outspoken firebrand, Hanson found many lessons and warnings from Galileo's trial that were relevant to Cold War America. This volume not only contains Hanson's best-known work in history and philosophy of science, but also highlights the breadth of his philosophical thought. Hanson balanced extreme versatility with a unified approach to conceptual and philosophical problems. Hanson's central insight is that philosophy and science both strive to render the world intelligible -- the various concepts central to our attempts to make sense of the world are interdependent, and cannot operate, or even be fully understood, independently. The essays included in this collection present Hanson's thinking on religious belief, theory, observation, meaning, cosmology, modality, logic, and philosophy of mind. This collection also includes Hanson's lectures on the theory of flight, Hanson's greatest passion.