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The Impact of Science
What’s New in Philosophy of Science?
So what’s going on in philosophy of science at the moment? Bora Dogan describes some of the current highlights.
Philosophers of science today are mainly concerned with two lines of inquiry. How does science give us knowledge of the world (if indeed it does)? And how do we make sense of current scientific theories, particularly in physics and biology?
The first of these questions is the one with which the likes of Popper and Kuhn wrestled in the past (see previous page), but the debates have moved on. As David Papineau, of King’s College London, remarks, “Nobody works with Popper’s assumptions any more.” These days, the debate is between instrumentalists (not of the musical variety) and realists. Instrumentalists argue that scientific theories do not tell us what the world is really like but they do allow us to make predictions about the world. Scientific theories are instruments for making predictions about the world. Their opponents, who are called realists, believe that scientific theories in fact describe the world and that the ability of a theory to make accurate predictions is an indication that it is successfully describing the world.
Bas van Fraassen takes the position that what scientists are trying to do is to describe the way the world really is, not merely to make mathematically accurate predictions. However, he agrees with the instrumentalists that one can never know the truth of such claims and can only judge theories on how good they are at making predictions. He calls this position ‘constructive empiricism’.
Philosophy of physics
Quantum mechanics describes how the world behaves at the subatomic level. As a tool for making predictions about the interaction of fundamental particles it is a highly successful scientific theory. But as a description of what the world is really like, it challenges both reason and intuition. Central to the theory of quantum mechanics is Heisenberg’s uncertainty principle, which says that certain properties of particles, such as position and momentum, cannot be measured accurately at the same time. If you try to measure the position of a particle with a high degree of accuracy you cannot measure its momentum very precisely, and vice versa. It doesn’t matter how good your measuring devices are because this limitation exists in principle. According to the Copenhagen Interpretation of quantum mechanics, this indeterminancy is an inherent property of particles at the quantum level.
Had it been restricted to the realm of subatomic particles the uncertainty principle may not have made such an impact on the philosophy of science. A thought experiment known as ‘Schrödinger’s Cat’ demonstrates that the uncertainty affects the world on an everyday scale too. Suppose we devise a contraption that uses the decay of a radioactive atom as a trigger to set off a mechanism that kills a cat. The radioactive atom is in an indefinite state – neither ‘decayed’ nor ‘not decayed’ – until a measurement is made to find out which is the case. Since the state of the atom determines the state of the cat – whether it is dead or alive – the cat is also in an indefinite state. It seems that inherent uncertainty can be a property exhibited by macroscopic objects as well as quantum particles.
The idea of a cat in a state of limbo is, of course, rather counterintuitive. Philosophers and physicists have been trying since the 1930s to interpret quantum mechanics in a way that brings it in harmony with common sense. One alternative to the Copenhagen Interpretation is the Many- Worlds Interpretation, which postulates the existence of countless parallel universes, one for each possible quantum state. According to this view, the cat in our thought experiment is alive in some universes and dead in others, without any uncertainty. Which is good and well if you like the number of your universes to be big. Not surprisingly, the search continues for a reasonable solution to the philosophical problems of quantum mechanics.
Philosophy of biology
The explanation of biological traits such as the greenness of plants or the stripes of a tiger seem to differ essentially from explanations in other sciences. A plant, it is said, is green because this trait facilitates photosynthesis, which is necessary for the plant’s survival. Likewise, a tiger has stripes because stripes act as camouflage and help the animal hunt its prey. In general, explanations in biology have a form whereby the consequences of a trait account for the presence of that trait. Such explanations are called functional. In contrast, non-biological explanations give the cause of a trait as the reason for the consequences of having that trait. We may refer to these explanations as causal.
Until recently philosophers accepted functional explanations as legitimate when applied to biological organisms. But most philosophers of biology no longer hold this view. Functional explanations are now seen as shorthand for what are in fact causal explanations. Thus the stripes of a tiger are not explained by the fact that they will camouflage the animal in the future but by the fact they have camouflaged its evolutionary ancestors in the past and have been chosen by natural selection as one of the tiger’s characteristics. The theory of evolution itself is the focus of some philosophical concern, including the question of whether it has any power to make predictions as other scientific theories do.
In 1996 an article written by Alan Sokal, a professor of physics at New York University, was published in the academic journal Social Text. The article purported to show that science would be liberated from the Western dogma of the existence of a physical reality independent of our perception of it, i.e. an objective reality, thanks to developments in the theory of quantum gravity. The author simultaneously published a letter in Lingua Franca explaining that the article was a hoax, concocted of pseudoscience, academic buzzwords and illogic. He had written it to find out whether “a leading North American journal of cultural studies [would] publish an article liberally salted with nonsense if (a) it sounded good and (b) it flattered the editors’ ideological preconceptions?”
What was Sokal trying to prove? By his own account he wanted to show that intellectual laziness and lack of rigour had become widespread in the social sciences. The editors of Social Text would not have published his article if they had bothered to have it reviewed by someone knowledgeable in either physics or mathematics; after all, the article was about quantum mechanics. Sokal argues that a prevalent subjectivist thinking, indiscriminately embracing everything from New Age mysticism to creationism, is undermining the importance of such fundamental concerns as facts, evidence and proof.
The progress of science over the last century is quite unlike any intellectual advancement made by humans before. For one thing, certain fields such as quantum mechanics are practically impenetrable to all but the specialist. We are becoming both increasingly uninformed of, yet influenced by, the development of science. This affects the relationship between science and society, perhaps adversely. Philosophers today must attend to the details of science if they are to bridge this divide.
© Bora Dogan 2002
Bora Dogan studied philosophy at the London School of Economics and is a UK Editor of Philosophy Now.