From owner-bhaskar Sun Jul 7 12:31:31 1996 Date: Sun, 7 Jul 1996 10:28:03 -0600 Message-Id: <> From: Hans Ehrbar <> Subject: rts2-02 Introduction The aim of this book is the development of a systematic realist account of science. Such an account must provide a comprehensive alternative to the positivism which since the time of Hume has fashioned our image of science. Central to the positivist vision of science is the Humean theory of causal laws. It is a principal concern of this study to develop some new arguments and show how they relate to more familiar ones against this still widely accepted theory. In particular I want to argue that not only is a constant conjunction of events not a sufficient, it is not even a necessary condition for a scientific law; and that it is only if we can establish the latter that we can provide an adequate rationale for the former. It has often been contended that a constant conjunction of events is insufficient but it has not so far been systematically argued that it is not necessary. This can, however, be shown by a transcendental argument from the nature of experimental activity. It is a condition of the intelligibility of experimental activity that in an experiment the experimenter is a causal agent of a sequence of events but not of the causal law which the sequence of events enables him to identify. This suggests that there is a ontological distinction between scientific laws and patterns of events. Obviously this creates a prima facie problem for any theory of science. I think that it can be solved along the following lines: To ascribe a law one needs a theory. For it is only if it is backed by a theory, containing a model or conception of a putative causal or explanatory 'link', that a law can be distinguished from a purely accidental concommitance. The possibility of saying this clearly depends upon a non-reductionist conception of theory. Now at the core of theory is a conception or picture of a natural mechanism or structure at work. Under certain conditions some postulated mechanisms can come to be established as real. And it is in the working of such mechanisms that the objective basis of our ascriptions of natural necessity lies. Introduction 13 It is only if we make the assumption of the real independence of such mechanisms from the events they generate that we are justified in assuming that they endure and go on acting in their normal way outside the experimentally closed conditions that enable us to empirically identify them. But it is only if we are justified in assuming this that the idea of the universality of a known law can be sustained or that experimental activity can be rendered intelligible. Hence one of the chief objections to positivism is that it cannot show why or the conditions under which experience is significant in science. Most critics have emphasized its depreciation of the role of theory; this argument shows its inadequacy to experience. Moreover it is only because it must be assumed, if experimental activity is to be rendered intelligible, that natural mechanisms endure and act outside the conditions that enable us to identify them that the applicability of known laws in open systems, i.e. in systems where no constant conjunctions of events prevail, can be sustained. This has the corollary that a constant conjunction of events cannot be necessary for the assumption of the efficacy of a law. This argument shows that real structures exist independently of and are often out of phase with the actual patterns of events. Indeed it is only because of the latter that we need to peform experiments and only because of the former that we can make sense of our performances of them. Similarly it can be shown to be a condition of the intelligibility of perception that events occur independently of experiences. And experiences are often (epistemically speaking) 'out of phase' with events - e.g. when they are misidentified. It is partly because of this possibility that the scientist needs a scientific education or training. Thus I will argue that what I will call the domains of the real, the actual and the empirical are distinct. This is represented in Table 0.1 below:- Table 0.1 --------------------------------------------------------------------- Domain of Domain of Domain of Real Actual Empirical Mechanisms X Events X X Experiences X X X --------------------------------------------------------------------- 14 A Realist Theory of Science The real basis of causal laws are provided by the generative mechanisms of nature. Such generative mechanisms are, it is argued, nothing other than the ways of acting of things. And causal laws must be analyzed as their tendencies. Tendencies may be regarded as powers or liabilities of a thing which may be exercised without being manifest in any particular outcome. The kind of conditional we are concerned with here may be characterised as normic. They are not counter-factual but transfactual statements. Nomic universals, properly understood, are transfactual or normic statements with factual instances in the laboratory (and perhaps a few other effectively closed contexts) that constitute their empirical grounds; they need not, and in general will not, be reflected in an invariant pattern or regularly recurring sequence of events. The weakness of the Humean concept of laws is that it ties laws to closed systems, viz. systems where a constant conjunction of events occurs. This has the consequence that neither the experimental establishment nor the practical application of our knowledge in open systems can be sustained. Once we allow for open systems then laws can only be universal if they are interpreted in a non-empirical (trans-factual) way, i.e. as designating the activity of generative mechanisms and structures independently of any particular sequence or pattern of events. But once we do this there is an ontological basis for a concept of natural necessity, that is necessity in nature quite independent of men or human activity. In science there is a kind of dialectic in which a regularity is identified, a plausible explanation for it is invented, and the reality of the entities and processes postulated in the explanation is then checked. This dialectic is illustrated in Diagram 0.1 below. If a classical empiricist tradition in the philosophy of science stops at the first stage, a rival neo-Kantian or transcendental idealist tradition (discernible in the history of the philosophy of science) stops at the second. If and only if the third step is taken and developed in the way indicated above can there be an adequate rationale for the use of laws to explain phenomena in open systems, where no constant conjunctions prevail. It is the unthinking presupposition of closed systems together with the failure to analyse experimental activity (which presupposes open systems) that accounts for the most glaring Introduction 15 weakness of orthodox philosophy of science: viz. the nonexistence in science of Humean causal laws, i.e. of universal empirical generalizations, and hence the inadequacy of the criteria of explanation, confirmation (or falsification), scientific rationality etc., that are based on the assumption that a closure is the universal rule rather than the rare and (for the most part) artificially generated exception that I contend it is. It is because Result/regularity events; sequences; invariances (1) *classical empiricism* | | | | generative V model-building mechanisms | in models | | | +--+-----------------------+ | / \ | (3)------<---------------------- (2) *transcendental idealism* real empirical-testing imagined/imaginary Diagram 0.1. The Logic of Scientific Discovery our activity is (normally) a necessary condition of constant conjunctions of events that the philosophy of science needs an ontology of structures and transfactually active things. The position advanced here is characterized as transcendental realism, in opposition to the empirical realism common to the other two traditions. Both the neo-Kantian or transcendental idealist tradition and transcendental realism see the step between (1) and (2) in Diagram 0.1 as involving creative model building, in which plausible generative mechanisms are imagined to produce the phenomena in question. But transcendental realism sees the need for the step between (2) and (3) also, in which the reality of the mechanisms postulated are subjected to empirical scrutiny. Transcendental realism differs from empirical realism in interpreting (1) as the invariance of an (experimentally produced) result rather than a regularity; and from transcendental idealism in allowing the possibility that what is imagined in (2) need not be imaginary but may be (and come to be known as) real. Without such an interpretation it is impossible to sustain the rationality of scientific growth and change. A conception of science is argued for in which it is seen as a 16 A Realist Theory of Science process-in-motion, with the dialectic mentioned above in principle having no foreseable end. Thus when a new stratum or level of reality has been discovered and adequately described science moves immediately to the construction and testing of possible explanations for what happens at that level. This will involve drawing on whatever cognitive equipment is available and perhaps the design of new experimental techniques and the invention of new sense-extending equipment. Once the explanation is discovered science then moves on to the construction and testing of possible explanations for it. At each level of reality law-like behaviour has to be interpreted normically, i.e. as involving the exercise of tendencies which may not be realised. Emprirical realism is underpinned by a metaphysical dogma, which I call the epistemic fallacy, that statements about being can always be transposed into statements about our knowledge of being. As ontology cannot, it is argued, be reduced to epistemology this mistake merely covers the generation of an implicit ontology based on the category of experience; and an implicit realism based on the presumed characteristics of the objects of experience, viz. atomistic events, and their relations, viz. constant conjunctions. (These presumptions can, I think, only be explained in terms of the need felt by philosophers for certain foundations of knowledge.) This in turn leads to the generation of a methodology which is either consistent with epistemology but of no relevance to science; or relevant to science but more or less radically inconsistent with epistemology. So that, in short, philosophy itself tends to be out of joint with science. .