Experiments, Laws and Mechanisms
The empiricist view of scientific laws as general statements about regular patterns of observable events has already (in Chapter 3) been shown to be open to a number of serious criticisms.
The starting point for the critical realist argument is to note that such regular series of observable events are rather rare in nature. One of the very few such regular sequences is the movements of the planets in the solar system. This gives us the regular patterns of night and day, the seasons and so on. However, if we consider, for example, the weather, then on a day-to-day basis, prediction is notoriously difficult and unreliable, even when meteorology is a well-resourced and established science. This is because the actual sequence of climatic conditions in any particular place is the outcome of the interplay of many different factors (pressure gradients, air movements, electrical potentials, temperatures at different altitudes, humidity levels and so on).In Bhaskar's account, scientific experiment is a practical intervention which seeks to isolate just one mechanism, so that its operation can be studied without the interference of its interactions with other mechanisms. To go back to our earlier example of the simultaneous emergence of dragonflies (see p. 19) one might want to know whether it was caused by day length, by temperature or by some form of communication across the population. This could be tested experimentally by taking some dragonfly larvae into a laboratory where they could be isolated from one another but subjected to exactly the same conditions of temperature and light/dark sequences. Each of the other conditions could then be artificially controlled in turn, and the effects on emergence studied. Bhaskar's argument is that when a single mechanism is isolated in this way, regular event sequences can be ‘triggered'.
But since these have been produced by the scientific investigators, and it would be absurd to say that the laws of nature are produced by the actions of the experimenters, it follows that the laws of nature must be something else, something independent of the event sequences which are artificially produced in the experiment.In Bhaskars account, the laws discovered by experiments are ‘tendencies' of the underlying mechanisms, which may or may not issue in regular and observable event sequences when the mechanism is interacting with other mechanisms outside the artificial experimental situation. So, for example, further research might show that the underlying mechanism in the dragonfly case is the secretion of a particular hormone in response to a given temperature threshold. However, the action of this hormone might be affected by other physiological mechanisms linked to maturational stage, light-exposure, contact with other individuals of the same or other species and so on, such that in nature the temperature threshold often may not trigger emergence.
This account oflaws as tendencies ofmechanisms, as disclosed by scientific experiments, is the key ‘realist' conclusion from the analysis of experimentation. Experimentation as a practice would be unintelligible if the mechanisms and their tendencies under investigation did not exist independently of the activities and beliefs of the experimenters.
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- Contents
- Agazzi E. (ed.). Varieties of Scientific Realism: Objectivity and Truth in Science. Springer,2017. — 411 pp., 2017
- ORIGINS OF CONFLICT
- The Scientific Legitimacy of Mentalism?
- Exploitation in and through the Large Cooperative
- §36. The Method of Mechanics
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