The following points highlight the five main roles of theory in geography. The roles are: 1. Theory as Orientation 2. Theory as Conceptualisation and Classification 3. Another Task of Theory – Summarising 4. Theory Predicts Facts 5. Theory Points to Gaps in our Knowledge.
Role # 1. Theory as Orientation:
A major function of a theoretical system is that it narrows the range of facts to be studied. Any phenomenon and object may be studied in many different ways. Each science and each specialisation within a broader field abstracts from reality, keeping its attention upon a few aspects of given phenomena rather than upon all aspects. Only thus can the work of science be managed. The broad orientation of each field, then, focuses upon a limited range of things, while ignoring or making assumptions about others.
It is in the light of these considerations that much of the nineteenth-century geography may be understood, for a major task of great geographers of the century was to define the task and object of the study for the future science. Theory, then, helps to define which kinds of facts are relevant.
Role # 2. Theory as Conceptualisation and Classification:
Every science is also organised by a structure of concepts, which refer to the major processes and objects to be studied. It is the relationships between these concepts which are stated in the facts of science. Such terms make up the specialised vocabulary that the scientist uses.
They change as the science develops, for different phenomena come to be of major importance. However, it is clear that if knowledge is to be organised, there must be some system imposed upon the facts which are observable.
As a consequence, a major task in any science is the development of systems of classification, a structure of concepts and an increasingly precise set of definitions for these terms. Much of geography witnessed the development of elaborate conceptual schemata. These pointed to certain phenomena as the most important to be studied and thus helped to organise the facts of man-land relations and social relations as well.
Role # 3. Another Task of Theory – Summarising:
A further task which theory performs is to summarise precisely what is already known about the object of study.
These summarises may be divided into two simple categories:
(1) Empirical generalisations, and
(2) Systems of relationships between propositions.
Although the scientist may think of his field as a complex structure of relationships, most of his daily work is concerned with a prior task – the simple addition of data, expressed in empirical generalisations. Geographers may be studying the ‘impacts’ of the environment upon man or vice- versa, in order to summarise the observation in a set of descriptions.
The demographer may tabulate births and deaths during a given period of time in order to ascertain the crude rate of reproduction. These facts are useful, and are summarised in simple or complex theoretical relationships.
As a body of such summarising statements develops, it is possible to see relationships between statements. A number of summarising propositions on various social actions and activities within the environmental perspective can be made, but they can also be seen as related to one another – ways by which a group gives a different status to an individual, pattern of asserting group control, ceremonial expression of group unity, etc.
Theorising on a still longer scale, some may attempt to integrate major empirical generalisations of an era. From time to time in any science, there will be changes in this structure of relationships between propositions. However, major shifts occurred in the mid-nineteenth century when a section of geographers, particularly German geographers, moved from older systems of theory towards a more acceptable system.
It is through systems of propositions that many of our common statements must be interpreted. Facts are seen within a framework rather than in an isolated fashion. Let us look at a few examples – ‘Nature is merely an adviser’; ‘Migration is a reflection of cultural diffusion’; ‘The crime rate is higher in slum areas than in middle class areas’.
If we study such apparendy simple statements more closely, it will be clear that behind each of them is a complex series of observations, a set of assumptions about the effect of social factors upon behaviour, and a system of propositions about the way in which groups act.
There is an implicit or explicit fact- chain or theory which gives such simple statements their full meaning. Theoretical clarity demands that the scientist must be more conscious of the thought system being employed than is the average man.
Role # 4. Theory Predicts Facts:
If theory summarises facts and states a general uniformity beyond the immediate observations, it also becomes a prediction of facts. This prediction has several facts. The most obvious is the extrapolation from the known to the unknown. For example, we may find that educated women have relatively lower fertility rate as compared to the illiterate women and as a result the crude birth rate among the educated women declines.
Thus, if education is spread or introduced into a native rural culture one can find this process taking place, i.e. of falling birth rate with increasing literacy and education. We can, thus, predict that in a region where education has already been introduced, the region experiences declining/falling birth rate.
We expect the same patterns simply because:
(1) We believe we know which factors cause these patterns, and
(2) We believe that these factors will be found in the new situation.
This is a common sense way of saying that behind our empirical generalisations is a body of theory. A given theory may be incorrect, but it does make prediction about observation of phenomena. It is a set of directions, stating how certain operations, observations and calculations are to be made with a prediction about the outcome.
Role # 5. Theory Points to Gaps in our Knowledge:
Since theory summarises the known facts and predicts the facts which have not yet been observed, it must also point to areas which have not yet been explored. As noted above, the simple fact of prediction suggests where to test the knowledge. If a theory states a general relationship, such as inverse correlation between income and fertility, we can see immediately where further facts might be sought.
We can break our income classes into smaller groups to see whether fertility might be higher (instead of lower) at the extreme upper income groups; we can ascertain whether this pattern is to be found in rural areas or in urban areas, or in other countries; or we can study the historical relationship between income and fertility. These are only examples.
However, theory also points to gaps of a more basic kind. While these gaps are being filled, changes in the conceptual scheme usually occur. It might be noted, in addition, that ‘seeing the gap’ is very easy once it has been seen.
An example may be taken from man- environment relationship. Although a substantial body of knowledge was built upon concerning the impacts of environment on human activities and its control over the activities of human groups with relatively inferior ‘genre de vie’, but no attention was paid to the responses expressed by human groups with superior ‘genre de vie’ possibilists.
This was a major gap in the deterministic theory. Such a gap would not be visible if our facts were systematised and organised. As a consequence, it can be said that theory does suggest where our knowledge is deficient. However, it becomes clear to us why one research problem is productive and another sterile.