Dealing with the Duhem-Quine thesis in financial economics: can causal holism help?

Acceptance of the Duhem–Quine thesis implies a recognitionthat empirical tests of individual hypotheses are in fact testsof individual hypotheses in conjunction with the networks fromwhich those hypotheses are derived. This leads to a problemin the evaluation of disconfirming evidence: is it the individualhypothesis or the network that is refuted? This paper examineshow financial economists deal with this ‘joint-testing’problem in their empirical evaluation of the efficient marketshypothesis. Causal holists argue that the holistic testing theyespouse circumvents the difficulties surrounding joint-testingproblems. This paper assesses whether a causal holist approachcan resolve the ambiguity surrounding the evidence against theefficient markets hypothesis. It concludes that, without a resolutionof the ontological–epistemological tension in causal holismidentified by Fleetwood (Cambridge Journal of Economics, 2002,vol. 26, 27–45) and a clearer outline of the nature ofholistic testing, causal holism cannot help financial economistsdeal with the implications of the Duhem–Quine thesis forempirical testing.