Alexander James Bird

The replication (replicability, reproducibility) crisis in social psychology and clinical medicine arises from the fact that many apparently well-confirmed experimental results are subsequently overturned by studies that aim to replicate the original study. The culprit is widely held to be poor science: questionable research practices, failure to publish negative results, bad incentives, and even fraud. In this article I argue that the high rate of failed replications is consistent with high-quality science. We would expect this outcome if the field of science in question produces a high proportion of false hypotheses prior to testing. If most of the hypotheses under test are false, then there will be many false hypotheses that are apparently supported by the outcomes of well conducted experiments and null hypothesis significance tests with a type-I error rate (α) of 5%. Failure to recognize this is to commit the fallacy of ignoring the base rate. I argue that this is a plausible diagnosis of the replication crisis and examine what lessons we thereby learn for the future conduct of science.

Scientific Realism stands or falls with Inference to the Best Explanation. Realism cannot be accepted if one has reason to think that Inference to the Best Explanation cannot lead to the truth, or is unlikely to. Peter Lipton raises three important problems for his model of Inference to the Best Explanation: Voltaire’s objection, Hungerford’s objection, and the problem of Underconsideration. In this paper I show that Lipton’s own solutions do not fully answer those problems. I argue that what is required to solve these problems is for our conception of explanatory goodness to be truth-conducive because it is sensitive to the way the world actually is. I suggest that the cognitive psychology of exemplars, as described by Kuhn, may provide an answer.

In this paper I argue that it is not a priori that all the laws of nature are contingent. I assume that the fundamental laws are contingent and show that some non-trivial, a posteriori, non-basic laws may nonetheless be necessary in the sense of having no counterinstances in any possible world. I consider a law LS (such as 'salt dissolves in water') that concerns a substance S. Kripke's arguments concerning constitution show that the existence of S requires that a certain deeper level law or variants thereof hold. At the same time, that law and its variants may each entail the truth of LS. Thus the existence of S entails LS. Consequently there is no world in which S exists and fails to obey LS. I consider the conditions concerning the fundamental laws that would make this phenomenon ubiquitous. I conclude with some consequences for metaphysics.