From Gerry Harant
Andrew Baker says, following David Hume, that we cannot be sure the sun will come up tomorrow based on the understanding that it has always come up before (24 November, p 22). From this he argues that science cannot establish the existence of the causal links required to apply the precautionary principle and take action against threats such as global warming.
The global warming deniers are not troubled by such philosophical niceties when they make their disastrous decisions, which affect all of the planet.
Their arguments are based on the certainties of the fossil fuel market and the absolute truths of the stock exchange.
They can rely on their deep insight that superior power beats superior knowledge every time.
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Unlike Baker, I feel quite capable of coping with the awful knowledge that in our misguided zeal to expose the near certainty of global catastrophe, we may well be inflicting irreparable damage on somebody’s belief in what they heard in introductory philosophy.
Baker’s conclusion that science should offer probabilistic predictions to policy-makers may be both sensible and important. But it is not rationally justifiable by his own arguments. If we invoke Hume’s doubts about induction to undermine causal explanations, then we must accept that they apply equally to probabilities.
The measurements that supported a given probability in the past may not do so in the future. The fact that things predicted with a high probability have, in the past, proved more likely to happen than those with a low probability does not mean that they will continue to do so.
To appeal to Karl Popper’s thesis that scientists should not pursue truth but should seek to falsify their hypotheses does not help. That thesis rests on the inductive assumption that, once refuted, a hypothesis will prove false in future.
High Wycombe, Buckinghamshire, UK
•Hume realised that his demonstration of the impossibility of establishing causation had huge implications, especially since it meant that even using probabilities was problematic. But probability, Hume said, was the best way out that we knew of. Somehow we must reconcile his arguments to achieve practical outcomes like management.
Blackburn, Victoria, Australia
