Manipulating Spins: Causality and Decoherence

Abstract

In a previous paper (Samaniego 2013) I criticized the manipulability theory of causal explanation (Woodward Making Things Happen: A Theory of Causal Explanation. New York: Oxford University Press, 2003) for its lack of applicability to causal patterns where two causes are not independent form each other. At that time I also expressed then my intension to improve Manipulability theory rather than dismiss it, given its power as methodological tool for detecting genuine causes and improving scientific explanations.

The Manipulability theory offers a set of criteria to test whether a given causal relationship is genuine. When I applied those criteria to evaluate the effect of two different types of decoherence on the spin-echo decay (as postulated by Hemmo and Shenker’s (Studies in History and Philosophy of Modern Physics 36:626–648, 2005)), the correlation between the two causes rendered impossible to prove that the causal relationship was genuine. This outcome was counterintuitive, however, given the abundant experimental evidence and medical applications that support the empirical adequacy of Hemmo and Shenker’s decoherence-based explanation of the spin-echo decay.

In 2011 Woodward proposed a strategy to resolve an analogous difficulty in an identical causal pattern that related two types of cholesterol to heart disease. In this paper I apply Woodward’s solution strategy to the Spin-Echo case, and explore the consequences regarding both models of causation and foundations of statistical mechanics.