June 24, 2006

Were the eye not attuned to the Sun,/ The Sun could never be seen by it. — Goethe

While writing this verse, the great German poet Goethe was intuitively expressing a scientific truth in poetic language. In the second half of twentieth century, Norwood Russell Hanson expressed a similar notion in his idea of theory-laden observation in scientific language.

He elaborated upon the idea in his famous book Patterns of discovery: an inquiry into the conceptual foundation of science. Theory-laden observation is the concept which maintains that our observation is informed by theory.

Hanson supports his idea of theory-laden nature of observation by marshalling a variety of examples from commonplace events. His purpose of quoting these examples is to consolidate his theory, on the one hand, and to negate the distinction of theory and observation in the received view, on the other.

He tries to show how sense data are moulded by different theories, interpretations and intellectual constructions. Gazing at the same object by two people does not necessarily mean that they see the same thing.

While studying Hanson, we have to take into consideration the difference between a physical state and a visual experience, as he believes that there is a great difference between the two. Some might put forward the objection that people have the same visual experience but interpret what they see differently.

Hanson’s idea of theory-laden observation rejects this kind of explanation. The investigation by Hanson into the nature of observation and its relation with theory broaches the issues which have not hitherto been explained by traditional accounts regarding observation and causality. He refuses to take the traditional accounts about observation for granted.

His account of interaction between visual experience and knowledge, and its connection with language, provides us with fresh accounts of knowledge formation in language. Hanson’s project is smaller in scale as compared to Kuhn’s elaboration of the concept of paradigm, and its role in scientific revolutions. Nevertheless, his idea is significant because it paved the way for the idea of paradigm which was later elaborated upon by Kuhn.

Hanson rejects the privileged position of observation over theory in the received view. The approach — which espouses that the idea that senses data of observers remains the same and difference in their interpretation results from differential interpretation — appears reductionist to Hanson. He claims: “There is more to seeing than meets the eyeball.”

Observation of x is shaped by prior knowledge of x. “There is a sense, in which seeing is a theory-laden undertaking.” The question that arises here is, what organises or shapes our visual data? Does the process of organising sense data and observing go hand in hand? How does an objective phenomenon look different to two observers?

Hanson’s attempts to address these questions takes him to the debate which is central to the philosophical theory of knowledge called epistemology. The idea of theory-laden observation by Hanson apparently deals with the issue pertinent to the philosophy of science, yet we can discern issues that are central to epistemology.

If we look at the debate between the received view and the idea of theory-laden observation regarding the nature of observation we find strands of Humian and Kantian thoughts. A perusal of Hanson idea reveals its affinities with Kantian idea of knowledge.

The examination of observation and different disputes about it in epistemology led Hanson to the conclusion that seeing is an experience. Unlike the received view, he holds that theory has privileges over observation.

Hanson says: “Theories and interpretations are there in the seeing from the outset.” We just cannot see things without having an idea of what we want to see. We rely on certain epistemic constructions of formal models of processes, perceptual and intellectual, by which we see and interpret something.

In other words, we can say that our background and training influences our observation. Hanson illustrates his argument by citing different examples: a trained physicist sees an X-ray tube in terms of electrical circuit theory, the theory of metal and glass structure, and thermionic emission, while an Eskimo baby sees the same thing as a lamp bulb or round shape. Put differently, our visual experiments are organised by theory.

Hanson’s most powerful argument in support of theory-laden observation is his assertion that training and background effect our observation. He cites an example of a professor of physics and a layman observing an experiment in a laboratory.

The layman cannot see what the physicist sees. The layman is not blind, but he is blind to what the physicist sees. Here, the elements of the layman’s visual field, though identical with those of the physicist, are not organised for him as for the physicist. The same lines, colours and shapes are observed by both, but not in the same way.

Having looked at various examples in support of his argument, Hanson deduces that “the observer may not know what he is seeing. He aims only to get his observations to cohere against a background of established knowledge. This seeing is the goal of observation.”

One of the objections raised against Hanson’s view is that all normal observers, when looking at the same thing, have the same visual sense data. The difference is not in what they see but in the way they interpret what they see.

For instance, one individual looking at an object sees a steel cylinder and another looking at the same object sees a telescope. A follower of differential interpretation will reply that the object of observation or sense data is the same. When we ask both individuals to reproduce the visual experience, they will produce the same visual picture. But the difference will appear in their explanation.

So the question arising here is: how to explain this difference? Any answer takes us to the relationship between picture and visual data and its explanation in language. Even when we do not put the visual experience in language the difference still remains in the perception of both individuals.

If we accept the precedence of observation over interpretation then it follows that the world appears as an object that contains various versions of interpretation to be explained by observer. This kind of approach tends to segregate observation from explanation.

To explain something, we need to figure out the appearance or form of that something. Differential interpretation fails to provide an account of how the observation is organised. Hanson responds to differential interpretation by coming up with his idea of theory-laden observation.

Despite the above explanations, we are still left with the question: how to describe the organisation of visual experience or data? Immanuel Kant explained the organising principles or concepts, which are built in our mind and without which we cannot impose order on our sense perception. The organising process or principle of mind in Kant is not observable but can be discerned within the process.

Likewise, the organisation of visual data is discernable but cannot be verified. Hanson says: “Organisation is not itself seen as the lines and colours of a drawing. It is itself a line, shape, or colour. It is not an element in the visual field, but rather the way in which elements are appreciated.”

He argues that the organisation of any figure is nothing that registers on the retina along with other details. He convincingly writes: “Yet it gives the lines and shapes a pattern. Were this lacking we would be left with nothing but an unintelligible configuration of lines.”

The span of Hanson’s theory-laden observation and the explanation of organisation of observation are not only confined to observation alone. It also covers causality. Before acquiring the knowledge of something we ought to know what we are looking for.

Hanson believes training enables us to know what to look for. He thinks causes are theory-loaded from beginning to end. They are not simple, tangible links in the chain of sense experience, but rather details in an intricate pattern of concepts.

“Causes certainly are connected with effects; but this is because our theories connect them, not because the world is held together by cosmic glue.” For him, the world appears causally held not because it is causally held. It appears so because our theories connect them.

Here, his view about the world is analogous to Kant’s — with the difference that Kant holds that the mind is the organising principle. In his treatment of observation and causality, Hanson raises some important questions but does not supply us with any explanation.

For instance, he asks: “What is the difference between an individual who sees the zebra as black with white stripes and another individual who sees it as white with black stripes?” He comments that there is nothing optical about it and there might be a context, where such a difference could be important.

Nevertheless, he absolves himself from the duty of explaining it by locating its answer in the genetics of animal pigmentation. Likewise, he puts the onus of answering the question about the same visual pattern being seen differently on psychology. It might have saved Hanson from detour and enabled him to focus on the subject matter, yet it comes at the cost of a holistic approach to the issue at hand.

An important point about Hanson’s arguments is that they cross the boundaries of natural science and deal with issues central to epistemology and philosophy. At the same time, they suffer from the constraints resulting from the dichotomy of knowledge into watertight compartments of specialisation.

These disciplines hold a monopoly over investigation of a particular issue because they claim to posses the required tools of research. Whenever a scientist faces difficulty in addressing a particular problem, he leaves the issue to be dealt by the people who hold authority over the explanation of the problem.

Hanson successfully undercuts the theory/observation distinction of the received view. The natural corollary of his concept is the rejection of the received view idea of scientific progress, which implies that the transition from one theory to another is cumulative.

The theory is central to Hanson’s view of observation and scientific progress. The significance of his theory can be better-valued if we take into consideration its effects on the subsequent discourses and developments.

For instance, his influence on Thomas Kuhn was considerable. Thus, he appears before us as a precursor of Kuhn’s idea of paradigm. J.E. McGuire includes Hanson among the writers who rejected the epistemologically motivated distinctions of much of the philosophy of science current in his time.

If science has to remain true to itself, it must, in the words of Karl Popper, perpetually challenge and criticise its own conclusions. But it cannot do all this by its own.

Ultimately science is dependent upon its practitioners’ strength to break the orthodoxies developed with the passage of time. The challenge comes from the practitioners of science, whose practice and investigation is dependent upon a point of view.

In science, this point of view is usually determined by a scientific theory. And Hanson’s argument of theory-laden observation had strength by which he undercuts the traditional orthodoxy of the received view. Hanson did this not to monopolise the discourse of observation in science, but to make science true to itself and to keep the door of scientific progress open.

The writer teaches at the Karakuram International University, Gilgit. Email: azizalidad@hotmail.com

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