Chapter 2 - Learning and Truth

Summary

Philosophy of Science

Let me first say that I am a realist, with the claim that there is a real world, even if that world is not completely and perhaps not reliably observed, and science should try to explain it, with the aid of theory. This stands in contrast with positivism, which says that we should only deal with what is observed, without theory, which was considered to be metaphysical speculation. This stance is not tenable, and has been superseded, in the philosophy of science, by the view that observation and interpretation are guided by theory, and are thus ‘theory laden’. If one claims, in positivism, that the theory is not about ‘what exists’, and only observation is valid, it becomes a mystery how the theory could ‘work’, help in dealing with the world. And what about the time that microscopes were not yet there: did microscopic things not exist at the time?

Observation and interpretation not only includes explicit theoretical propositions, but a host of subsidiary or ‘background’ assumptions, often tacit or taken for granted, about how the world works. The challenge then is to craft implications of the theory that can be observed, to test the theory. Any falsification will again include subsidiary assumptions that one can criticise to disarm the falsification and save the existing theory. Furthermore, the falsifying proposition also is value laden, and hence is not an indisputable fact.

There is the story of the planets Neptune and Vulcan. The planet Neptune appeared to deviate from Newtonian physics, but the apparent anomaly was eliminated with the discovery of the planet Mercury, which could explain the deviation. Another anomaly then concerned Mercury. It was postulated that this anomaly was due to yet another planet called ‘Vulcan’, which could not be observed, but this could be explained away with the argument that it was so near to the sun that its light was overpowered by that of the sun, but this time that planet was never found, and the anomaly did falsify Newtonian physics, and could be explained by relativity theory.

How can we know whether a theory is true? Karl Popper (1959) proposed that theories cannot be proven but only falsified.