Reality as Differentiated: Closed and Open Systems

For the moment, we have to consider yet another feature of the world which is disclosed by the possibility (and necessity) of scientific experiment, and also the application of science in technology.

However, in other cases, such as the extraction of pure samples of chemical elements from the mixtures and compounds in which they generally exist in nature, or the rearing of organisms under artificially controlled conditions, experiment is a practical possibility. Where mechanisms coexist and interact with one another in contingent ways, Bhaskar speaks of ‘open’ systems. Where mechanisms naturally exist in isolation (or there is a balance of interfering mechanisms), or where there is artificial isolation (or control of interfering mechanisms), Bhaskar speaks of ‘closed’ systems. Experiments would not be either possible or necessary if all mechanisms naturally occurred in closed systems: the world would be as the empiricist ontology takes it to be.

When experimental work under controlled conditions discloses the properties and powers of particular materials - for example, that certain plastics are good electrical insulators, or that electric currents generate magnetic fields - then this knowledge can be applied to make instruments like electrical safety devices, electric bells, locks and so on. But this application makes sense only on condition that the causal powers attributed to the materials concerned on the basis of study in closed systems continue to be their properties in open systems. So, both scientific experiment and the application of science presuppose that causal mechanisms can exist and act in either open or closed systems, and that the laws of nature (but not necessarily regular event sequences) apply ‘transfactually’ (that is, in both open and closed systems). Bhaskar calls this feature of the ‘intransitive dimension’, as disclosed by the analysis of experiment and scientific application, its ‘differentiation’. The world thus exists independently of our beliefs about it, is differentiated, and is stratified. These are the key claims made by critical realists about what the world must be like if it is to be a possible object of scientific investigation.

The Transitive Dimension

We can now turn to the second set of answers to the question, ‘What must be the case for science to be possible?’ These concern what the human scientific investigators, their modes of communication and society must be like for science to be possible, and together they constitute what Bhaskar calls the ‘transitive’ conditions or dimension of science. Here, critical realism is close to Kuhn, Feyerabend and the sociologists of science, in recognizing (against the empiricist tradition) the social and historical character of science. Science as a social practice presupposes the institutions of scientific communication and criticism, and the role of metaphor in scientific reasoning implies the existence of a culture which can be drawn on for the conceptual ‘raw materials’ for the production of scientific knowledge.

The distinctive features of critical realism as a theory of science, then, are:

(i) it recognizes science as a social practice, and scientific knowledge as a social product;

(ii) it recognizes the independent existence of the objects of scientific knowledge;

(iii) it has an account of scientific experiment and discovery as simultaneously material and social practices in virtue of which both (i) and (ii) are sustained.

By contrast, Kuhn, Feyerabend and constructionist accounts of science fully recognize the social character of science, but have great difficulty in maintaining a coherent account of the independent reality of the objects of scientific knowledge. On the other hand, empiricist accounts of science have little or no room for the social dimension of scientific practice, though neither can they fully sustain the independent reality of the objects of scientific knowledge. At best, they are restricted to a view of reality as a flow of ‘surface’ events, and science as a summary record of them.