Science, philosophy of

4. Contemporary philosophy of science: foundational issues from current science

Many of the most interesting issues in current philosophy of science are closely tied to foundational or methodological concerns about current scientific theory. One fertile source of such concerns is quantum theory. How much of a revolutionary change in our general metaphysical view of the world does it require? Is the theory irreducibly indeterministic or do ‘hidden variable’ interpretations of some sort remain possible despite the negative results? What does quantum mechanics tell us about the notion of cause? Does quantum mechanics imply a drastic breakdown of ‘locality’, telling us that the properties of even vastly spatially separated systems are fundamentally interconnected – so that we can no longer think of, for example ‘two’ spatially separated electrons as separate, independent ‘particles’? More directly, is there, in view of the ‘measurement problem’ a coherent interpretation of quantum mechanics at all? (It has been argued that when the theory is interpreted universally so that all systems, including ‘macroscopic’ ones, such as measuring apparatuses, are assigned a quantum state then the two fundamental principles of quantum theory – the Schrödinger equation and the projection postulate – come into direct contradiction (see Bell’s theorem; Field theory, quantum; Quantum measurement problem; Quantum mechanics, interpretation of; also see Randomness; Statistics).)

Although perhaps attracting relatively less attention than quantum theory, the other two great theories that form the triumvirate at the heart of contemporary physics – relativity (both special and general) and thermodynamics – pose similarly fascinating problems. In the case of relativity theory, philosophers have raised both ontological issues (for example, concerning the nature of spacetime) and epistemological issues (concerning for example the real role played in Einstein’s development of the theory by Machian empiricism, the role of allegedly crucial experiments such as that of Michelson and Morley (see Crucial experiments), and the evidential impact on the general theory of the Eddington star-shift experiment). There are also important issues about the consistency of relativity and quantum theory – issues that in turn feed into the more general questions concerning the unity of science and realism (see General relativity, philosophical responses to; Relativity theory, philosophical significance of).

Thermodynamics raises issues about, amongst other things, probability and the testing of probabilistic theories, about determinism and indeterminism, and about the direction of time (see Thermodynamics; Determinism and indeterminism; Duhem, P.M.M. §2; Time). Other current areas of physics, too, raise significant foundational issues (see Chaos theory, Cosmology).

For a long time, philosophy of science meant in effect philosophy of physics. A welcome broadening-out has occurred recently – especially in the direction of philosophy of biology. The central concern here has been with foundational issues in the Darwinian theory of evolution (or more accurately the neo-Darwinian synthesis of natural selection and genetics). Questions have been raised about the testability and, more generally, the empirical credentials of that theory, about the scope of the theory (in particular what it can tell us about humans and human societies), about the appropriate ‘unit of selection’ (individual, gene, group), about what exactly are genes and what exactly are species, and about whether evolutionary biology involves distinctive – perhaps even in some sense ‘teleological’ – modes of explanation (see Darwin, C.R.; Ecology; Evolution, theory of; Functional explanation; Genetics; Huxley, T.H.; Life, origin of; Linnaeus, C. von; Sociobiology; Species; Taxonomy; Wallace, A.R.). More recently philosophy of biology has started to widen its own scope by considering issues outside of evolutionary theory (see Molecular biology; Medicine, philosophy of), where, however, issues of reductionism and of the possibility of distinctive modes of explanation still loom large.