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The Relation between Theory and Observation in Science as Seen by N. R. Hanson

1 Introduction

According to logical positivism, scientific theories can be verified by facts since observations of the world or the universe are not just theory-dependent, but rather, are contingent on objective investigation. Thus, the dispute between competing theories can be resolved by appealing to this impartial-objective source. In this respect, N. R. Hanson (1924–1967) argues that since each scientific theory formulates its own style in identifying what it sees, all the observations are mainly theory-laden and the conceptual framework determines the way we view the world, and this is why we observe the same things from different angles and perceive the same objects in a different way. In this chapter, Hanson’s views with regard to the relation between theory and observation, and the factors that determine the aforementioned relation will be examined.

Although discussions on science are ongoing since past millenniums, the scientific revolutions that have led to the development of modern science have been extraordinarily influenced by the discussions of what is science and scientific knowledge. In particular, one of the basic claims of the traditional understanding, especially expressed in a widespread manner about science, is the concept that science is exclusively based on practical experiments and observations.

This kind of view became widespread at first glance, especially when scientific developments were projected by scientists such as Galileo and Newton in the seventeenth century. The idea made by Francis Bacon and his contemporaries – a basic discourse that “if we want to understand nature, we must refer to the nature not scripts of Aristotle” – is a key indicator of the scientific attitudes and approaches of their time (Chalmers, 2008: 10). Medieval [natural] philosophers of natural sciences and philosophical subjects had considered ancient philosophers, in particular Aristotle’s works, as the source of knowledge. But seventeenth-century philosophers were influenced by the revolutionary investigations of scientists like Galileo, and thus, began to see the experiment as a source of knowledge —particularly of scientific knowledge.←163 | 164→

This kind of understanding and attitude has since become widespread with the increasing success of science, which is expressed in J. J. Davies’s book On the Scientific Method (1968) as “Science is a structure based on facts” (Chalmers, 2008: 10). In a similar manner H. D. Antony’s expressions in his “Science and Its Background” are noteworthy with regards to Galileo’s scientific achievements in terms of showing the function of the experiments in scientific knowledge: “Galileo’s experiments and observations as an attitude that led to the break with the tradition were not too much. According to him, facts based on observation and experiment should be counted facts, not the ones attached to the ideas already adopted. The facts of observations could be or not be adapted to an adopted scheme of the universe, but what was important to Galileo was to acknowledge the facts and construct them in a way that conforms to the facts” (Antony 1948: 145; Chalmers, 2008: 10).

From this point of view, which can be described as a positivist approach, the so-called sciencetific process is related to observational situations based on a number of sensory data that scientists impartially perform. Theories and laws can be derived from the propositions obtained in this way, in other words, by means of observation proposals, which will create scientific knowledge. Now, if we look at the point of view of science that is called positivist science understanding at this point, there are two contradictory assumptions. One of these is that science has begun with observation. Second one is that observation is a solid basis from which scientific knowledge is derived (Chalmers, 2008: 40).

Given these two assumptions, the assumptions of logical positivism as a dilapidated form of coarse positivism, particularly as a debate on science in the twentieth century on what the relationship between theory and observation is, constitutes the centre of such discussion. The principle of “verifiability”, which is the basic principle of logical positivism, is roughly based on a sensory experiment. The function of sense experiment is to verify here. Condition of verification is also sensory experience. According to logical positivism, the fact that a scientific theory can be proved by direct observation means that it has general criteria that can be evaluated on an objective basis of scientific theories. That is why the observation language allows scientists who use it to see the same thing[s]‌ when they are looking at the same object. Thus, the debate between rival or competing theories can be resolved by referring to this impartial-objective source. According to these positivist scholars, nature is objectively known and there is no depth that cannot be explained in science; everything is superficial. The criterion of being scientific is also to get rid of all prejudices, prejudgments and unsubstantiated beliefs. According to positivist approaches, a theory comes from theoretical and observational propositions. This brings about the ←164 | 165→distinction between observational language and theoretical language. Each of these has its own set of terms: observational terms and theoretical terms. From this point of view, scientists perform science in three levels: (i) Firstly, observational data are expressed in the form of observational proposals consisting of observational terms. These are empirical data. For example, “This copper wire transmitted heat”. (ii) Secondly, empirical generalizations are obtained from these data: “Copper conducts heat”. (iii) Finally, these generalizations are explained by theoretical terms (Hung, 1997: 328). When we look at this scientific aspect of positivism, the empirical part is on one side, and the theoretical part is on another side. The empirical part derives from the theoretical terms of the empirical terms which express the observational data. Accordingly, each theory has a dual structure: the first is the part of the internal rules in which the propositions of the theoretical terms take place. Second part is of the “correspondence rules” that combines the propositions that come into play from theoretical and observational terms. These rules are rules that link theoretical terms to terms of observations (Carnap, 1996: 233; Hung, 1997: 328; Mormann, 2008, 13–167). If a theory will work, empirical generalizations must be deductive from the assumptions made through internal and mere rules of conduct.

2 Relation of observation and experimentation to theory

Relation of observation and experimentation to theory, and debates about the role of observation and experiment in science emerge in opposition to science design of positivism in general and logical positivism in particular claiming that science is based on data obtained on the basis of observation. K. R. Popper, the representative of the falsifying science understanding, claims that all experimental and observational findings in scientific activity are theory-dependent that it cannot be an independent observation and experiment from the theory (Popper, 1963). Along with Popper, in the history of philosophy of science, philosophers and historians like Pierre Duhem and A. Coyre have mainly addressed the relation between theory and experiment. They have presented striking examples from the history of science on this subject. According to Duhem, a physics theory is like a dictionary that is translated by itself. For that reason, a physics theory is a matrix of mathematical prepositions derived from a small number of primitives, aimed at presenting precise and accurate experimental instruments as simple as possible. According to the Duhem experiment in physics is not to observe a phenomenon simply; the experiment is the theoretical interpretation of the subject matter. The test consists of observing certain events first. It is enough for the senses to be careful and alert to do this observation. The experiment consists ←165 | 166→of the interpretation of the phenomena observed at the same time and it is not enough to be alerted and experienced to make this interpretation; it is necessary to know accepted theories and how these theories will be applied. Thus, according to Duhem, an experiment in physics is conducted with meticulous observations of phenomena and interpretation of these phenomena. This interpretation transforms tangible data collected in a realistic way into some abstract and symbolic representations matched to the important features of the theories accepted by the observer. The interpretations made about the phenomena through the theories accepted by the observer or the experimenter are an integral part of the experiments in physics. In addition, the theory will tell us about the experiment to be conducted or applied. When the experiment is conducted and the results are clearly observed, the theory puts them in order, to generalize and draw new experiments from them (Duhem, 1954: 147).

According to A. Koyre, who has an important view on what the relationship between theory and experiment is and how the theory and experiment play a role in science production, the real important role in the emergence of modern science is not observation or experiment, but rather experience based on a certain theory. Experience is to inquire nature in a natural way. This inquiry activity requires a language, which is a question for which questions are asked, and a dictionary, that is, a theory that allows the answers to be read and interpreted (Koyre, 1994: 110–111). According to Koyre, it is not an experiment that precedes the theory; it is not possible to make an experiment independent of the theory or to reveal what the result is. Theory sets the content of observation and experiment. In short, according to Koyre it is not possible to say that there is a fact independent from the theory; facts are always the facts of a certain theory; the language of the theory also makes the fact meaningful. The fact becomes meaningful only through a theory that determines itself.

3 Is there an independent observation and experiment in theory?

N. R. Hanson (1924–1967), one of the contemporary scientific philosophers who claims that observation and experiment are theory-dependent against positivism, proposing that there cannot be theory independent of observation and experiment, and takes experiment and observation based theory as basis of science, argues that there is no theory independent of observation and experiment language like A. Koyre. In his work titled “Patterns of Discovery” Hanson emphasizes that when describing what it each sees, each scientific theory creates its own style. For this reason, independent observation from theory is not the ←166 | 167→issue. Theories, which are conceptual frameworks, determine the point of view of the world, and for this reason according to Hanson it is possible for us to see the same thing[s]‌ from different angles, and that we also perceive the same objects differently (Hanson, 1958: 4–30).

When it comes to observation, it is generally considered as eye among five sensory organs and its activities. Looking at the act of sight, human beings often see through their eyes. When you look at the human eye, it can be said that the most important items are the lens and the retina. The retina composed of cone and rod nerve cells can be thought of as a screen on which the images of the objects of the external world are formed. It works like a photographic film, and it changes by light. In the visual act, the retina and the lens are the inner elements belonging to the eye itself, whereas the external dimension of the vision is formed of light. The human eye can only see through the aid of light. Vision is the product of an interaction of eye organs and light. The light rays that hit the object reach the lenses through the eye. Lens reflects these rays in such a way to be gathered at a point on the retina and thus picture of an object emerges in the retina. Another function is of visual nerves connected to the main brain cortex from retina. These nerves transmit information about the falling light to the centre of vision in the brain, so that vision occurs. The widespread view of observation when this process of visualization is carried on in the background claims that some of the features of the observer, that is, some of the features of the external world, are obtained directly in the same way with seeing capacity of brain and that two observers from the same place see the same object and view the same. Accordingly, the same light rays will cause the same pictures by focusing on the normal eye retina through eye lenses by multiplying the same object by the eye (Chalmers, 2008: 40–41). The argument in question is that each viewer must be able to see the same object and reach the same brain through the same eye nerves.

Now, at this point, Hanson’s objection is that the effective thing on experience of observer is neither the data in the form of light rays entering the eye, nor the images of the eyeball’s retinas when observing the same object. It is not possible to say that, although the same pictures appear in the eyes of two observers facing the same object in the same physical environment, they both have the same visual experience. According to Hanson, it is possible to say that there is much more in seeing than actions of eyeballs. Hanson claims that the same object is visible, the same images appear in retina, but the meaning of these images depends on other factors that are different from the biological and physical states that will affect the act of seeing in the observer. What the observer sees, in other words, when he looks at an object that is observer’s experience depends, in part, on his past experiences, knowledge, and expectations (Hanson, 1958: I).←167 | 168→

4 Observation and experiment are theory dependent

In scientific activities Hanson argues that the observer sees and his special experiences in a specific case are determined by not only pictures on retina but also by subjective experiences, explaining expectations and overall internal situation. “Imagine Johannes Kepler: imagine that he watches the sunrise on a hill. Tycho Brahe is next to him. Kepler thinks that the sun is constant, the earth is rotating. However, Tycho follows at least Aristotle and Ptolemaios in this regard: the earth is fixed and all other celestial bodies rotate around it. Do Kepler and Tycho see the same thing at dawn time in the east?” (Hanson, 1958: I). As such, Hanson gives different examples of what the seeing has to do with viewpoint. According to him, seeing the sun as a fixed or moving object is not just about the interpretation made by two different observers. Similarly, looking with the telescope and microscope clearly reveals the difference between the master and the novice. There is a big difference between dark and bright parts of images saw by less experienced and skilful master. Both people do not see the same thing, although both people use the same instrument and have a normal eye condition and look at the same object. It is quite possible to increase the number of these samples. The most known of these is the telescope that provided Galileo’s discoveries. What is mentioned above is that Galileo looks at the sky with telescope. The question at this point is the difference between Galileo and his contemporaries. “The doubts that competitors felt about accepting phenomena that Galileo learnt to see as Jupiter’s satellites must be due to the real difficulties they have faced was not because of prejudices but learning to “see” with coarse-telescopes” (Chalmers, 2008: 45; Hanson 1958: 46).

The point illustrated by the examples above according to Hanson is that observers see different things because they have different theoretical framework, different knowledge and belief. This situation cannot be treated as a matter of interpretation only because it affects what one sees (Hanson, 1964: 9). It is also not a question of having different interpretations of different visual images or data (Hanson, 1958: I). Because Hanson’s claim here is based on such an argument, with regards to perception, it is the only real experience that the observer directly relates to. However, these experiences are never unchanging, on the contrary they are things that can change. In short, these experiences may vary according to the status, knowledge and expectations of the observer. On the other hand, the physical causes give us pictures on the retina. However, it is not possible for the observer to establish a direct perceptual relation to these retinas as they are in their own experiences. In his widespread sense of observation, he claims that there is a one-to-one correspondence between the images that ←168 | 169→look popular and the experiences we experience in seeing. Hanson’s argument here is that we cannot see the exact same thing we want to see, no matter what it is. Images that appear in relation to the object we are looking at in retinas form part of the causes of what we see, while the rest is a large part that will be ignored, the internal state of our brains and our minds constitute other causes. In other words, here is a process analogous to the internal and external dimension of the act of vision. We saw things for a number of reasons, while constituting an external dimension and an internal dimension that we can say form other reasons. These reasons, which can be expressed as internal dimensions may vary between cultural situations, education, our knowledge and skills and expectations. As Hanson claims, the things that cause different things to be seen are the experiences of visual elements in the way they are comprehended. These are the knowledge and beliefs we need to realize beforehand.

Hanson claims that all observations are theory-loaded by giving examples from Gestalt psychology: “X observation is shaped by the previous knowledge of x” (Hanson, 1965: 48). He also argues that “another activity on observation shows itself on the language or signs we use to express what we know”. “A language that comes to mind from shapes, colours, indecisiveness and explanatory interpretations is well suited to ambiguous experimental conditions where indecision and even conceptual confusion can dominate. The observer may not know what he sees. His sole purpose is to make his observations consistent with the history of established knowledge”. Hanson’s claim here is a generally accepted claim. In particular, it is a requirement that the propositions expressing the observations or experimental data as Duhem claims like a dictionary for us to translate from a foreign language for to a language of a theory. The propositions expressing observational conditions can only be formulated through a theory, that is, in the language of theory. Such propositions may also have a value to the perfection of the theoretical and conceptual framework in question at the same time. When we think of the concept of “power”, this concept can take its meaning in a theory that only assumes a conceptual framework. There is a distinction between the concept of “power” used in Newtonian mechanics and the concept of “power” used on daily basis. The concept of power in Newtonian mechanics does not have any certainty every day, with an obvious meaning in Newtonian theory. Precisely and clearly expressed theories are preconditions for the accuracy of observational propositions. For this reason, theories come before observations. Hanson’s theory of being loaded can be summarized briefly as follows: all observations, words used in the observation are theory-loaded because they are connected to a context. In other words, it is possible to determine the meanings of phenomena only by the help of conceptual patterns in ←169 | 170→which words are connected to each other. Observations, events and data can be understood in an order determined by conceptual patterns. According to Hanson, what scientists see is actually related to their established knowledge and beliefs. As knowledge and beliefs change, so does the way in which they see objects. Language theory is used to describe what we see. In this context, the phenomena expressed with the help of language are related to language. The meanings of the phenomena depend on the use of the language. The use of the language results in seeing different things, and at the same time detects which phenomena are easily perceivable. In different contexts, words enter into different relationships with each other; they take place in different conceptual patterns. Besides, the meaning of a word is a function of the conceptual patterns that it has entered into words.

5 Conclusion

Lastly, debate as to whether theories or observation or experiment come first manifests itself as an important debate in the understanding of science developed against the positivist tradition. Dimensions of the debate extend from analyses of internal and external structures of physical objects, to the structure of the brain and mind. So, the dimensions of the debate are quite different. We, therefore, on the subject under discussion here, have argued the views of N. R. Hanson, one of the members of the conception of post-positivist science in the second half of the twentieth century.

As is known, Thomas Kuhn makes it clear that it is A. Koyre who is influential in the creation of his scientific understanding. In particular, Koyer examines the reasons behind the emergence of contemporary science out of positivist science. Presenting a new point of view, he has proved a new philosophy of science in a way that proves its claims by sifting through the records of the history of science. Particularly, Koyre’s assertions about the analysis and determinations of how scientists think about science activities and the reasons that scientists influence their thinking have an influence on classical science understanding. The inclusion of situations that can be deemed unscientific in realization of scientific production or activity in the context of a certain understanding, and the inclusion of all these in a thought frame, a conceptual framework and a linguistic framework, and at the same time that all these elements are inseparably intertwined, are a critique of many assertions put forward by the understanding of science that we can call positivism. One of these criticisms is the understanding that theory precedes observation and experimentation. It is not possible to have an independent, simple observation without a basic argument. Although Hanson is influenced ←170 | 171→by Koyre from many different sources, he considers the relation between theory and observation to be the same as Koyre. The most basic common points and bases of Koyre, Hanson and T. Kuhn are that theory is loaded with theory and a language of observation and experimentation independent of theory is impossible. According to the understanding that precedes the theory, theories are the medium of observing the world. An accepted law, proposition or theory, affects our beliefs and expectations. So, our experience is also influenced by it. For the scientific study, there is a need for accepted theories to show to the researcher which data to collect, how to interpret them, and which tools to use. Hanson and Koyre in the first place and Kuhn in the later do not accept the existence of an independent observation language lacking in terms of theoretical or intellectual and conceptual framework.


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