Bayesian Reasoning in Data Analysis: A Critical Introduction
Bayesian Reasoning in Data Analysis: A Critical Introduction
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DOI:
10.1198/jasa.2004.s357
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发表时间:
2004-12
影响因子:
3.7
通讯作者:
G. Woodworth
中科院分区:
文献类型:
--
作者:
G. Woodworth
While team-teaching a course on scientific reasoning, I stumbled on Giulio D’Agostini’s lectures and papers on Bayesian scientific reasoning for physicists and physics students, so it is a great pleasure to see the appearance of this book “. . . primarily addressed to physicists and other scientists” (p. vii). It joins a list of recent books, such as that by Spiegelhalter et al. (2002), written for advanced students and practitioners “who . . . will almost certainly have encountered, with increasing frequency, the term ‘Bayesian’ in articles, books and the media . . . ” (p. vii). D’Agostini dates his “largely self-taught” transition to Bayesianism from 1993. He is a passionate convert, making, as he says, “continual, sometimes sarcastic, criticisms of ‘conventional’ statistical methods.” Like many of us, he is “doggedly critical of these conventional methods,” because he feels “cheated by names and methods which seem to mean something they do not” (p. ix). Amen. Thus spake a physicist. Bayesians are mystified by the irrational persistence of the conventional statistical paradigm, particularly in undergraduate statistics “best sellers.” It is baffling that anyone can with a straight face define probability as long-term relative frequency, because that amounts to defining probability as the probability limit (or, if you prefer, the almost certain limit) of a relative frequency, which is as circular as defining a human being as the offspring of human beings. It is equally baffling that anyone could seriously claim that the probability of data given a hypothesis has a consistent relationship with the probability of the hypothesis given the data. Of course, conventional statistical reasoning professes to not understand the idea of the probabilities of hypotheses. Nevertheless, as D’Agostini points out, there are situations, such as diagnostic testing, in which frequentists are willing to assign probabilities to hypotheses, and in those situations the probability of a type I error is utterly unrelated to the weight of evidence for the hypothesis (Sec. 3.12.1). Of course, subjective probability is the answer; however, an aversion to subjectivity in scientific reasoning is the angel with flaming sword that bars many from the Bayesian garden. But as D’Agostini and many others have demonstrated, scientists are far from objective in their interpretation of observations (Press and Tanur 2001). D’Agostini earlier wrote that experienced physicists know that observations are the only objective things in science; transforming observations into knowledge involves many implicit and explicit beliefs. However, a form of objectivity can be recovered if scientific knowledge is understood to be a network of well-supported beliefs, “with fuzzy borders which correspond to the areas of present research.” His motto is “no one should be allowed to speak about objectivity, unless he has had 10–20 years of experience in frontier science, economics, or any other applied field” (D’Agostini 1999). Conventional statistical reasoning, with its significance-testing paradigm of probabilistic falsification, derives from Popper’s attempt to make an end run around the problem of induction by basing scientific reasoning on deductive reasoning; theories that make false predictions are logically false. However tidy that scheme seemed for a time, “in practice a single conflicting or counterinstance is never sufficient methodologically to falsify a theory” (Thornton 2002). Significance testing, the probabilistic rendition of Popperian falsification, has been so eloquently discredited by statisticians and scientists of all stripes that one marvels that the topic is still taught in most introductory undergraduate statistics textbooks as the paradigm of statistical reasoning (Parkhurst 1997). It comes as no surprise that after a conventional statistics course or two, students come to view conventional statistical practices as somehow naturaland self-evident when in fact they are demonstrably neither. For that reason, statistics textbooks must take seriously the need to teach the foundations of statistical reasoning from the beginning, namely: