THEORY

A simple definition of theory may be seen in the sequence: conjecture, hypothesis, theory. Here the word is used to identify a construct assumed to be true that forms the basis for prediction and/or explanation, thereby forming the basis for accumulation of further empirical knowledge. In the conjecture-hypothesis-theory sequence, there is no formal distinction between the terms, but there is widespread, informal recognition that it reflects increasing certainty or confidence in the scientific underpinning of the idea. It is embraced colloquially in the expression ‘I have a theory about that’.

The infinitely more complex use of the word emerges in expressions such as ‘a body of theory’ or ‘scientific theory’. Here theory is being used to designate sets of linked ideas (some of which, at least, are often called laws) that underpin and pervade the entire scientific endeavour or some distinctive and substantive portion of it, such as thermodynamics or an entire discipline. This use of the term has not only been the focus of multiple attempts to create a satisfactory definition in the immediate sense, but the very content, nature, and role of the concept have been, and continue to be, open to debate.

One useful way of grasping the general purpose of theory is to view it as any generalisation that goes beyond available data. science is not just about accumulating information, nor indeed just about explaining experiences open to the human senses; it seeks generalisation, simplification, unification of the known and prediction and preparation for the, as yet, unknown. At its deepest level, the debate about the nature and role of theory has been conducted within the philosophy of science.

Most natural-environmental scientists have not received any training in philosophy, but have grown up in scientific cultures placing tremendous emphasis on field research. Consequently, there is a [Page 1090]widespread tendency to view theory in terms of the diametrical differences often drawn between logicalpositivism and critical rationalism (or their derivatives). The simplified version of this debate manifesting in the environmental sciences tends to emphasise the normative nature of theory and certain antipodean positions: (1) observation and theory, (2) verification and falsification and (3) the role of theory in scientific discovery and scientific justification. Coupled with a preference for field research, these ideas have tended to foster an aversion to theory among many environmental scientists. For most philosophers of science, the logical positivist/critical rationalist debate is long over. In any event, such a debate would be less significant than one focused upon the role of theory in something such as relativism, where knowledge is seen as the product of social construction and changes in theory do not imply convergence on some external truth, versus its role in realism, where truth is seen as an external reality upon which science is converging.

Defining theory as dependent upon one’s philosophy of science, it is possible to offer some useful ideas stemming from modern naturalised philosophies of science. Foremost, theory is pervasive and hierarchical. At a foundational level, theory rests upon embedded ontology, Weltanschauung (world view or world outlook), regulative principles, or myths— metaphysical elements (see metaphysics) that are unfalsifiable and empirically untestable. At a more superficial level, all observations are made in the light of theory, and consequently are theory laden. However, only in its most extreme form does the theory-laden nature of observation preclude adequate, independent testing of theory. The contextual distinction between exploratory theories (e.g. those that underpin belief in the utility of a radio telescope) and explanatory theories (e.g. the astronomical beliefs being investigated using the radio telescope) not only highlights the importance of theory, it often assuages the concern about theory-laden observation.

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