Cooper M W
Department of Cardiology, University of Texas Health Center, Tyler 75710.
Theor Med. 1992 Dec;13(4):349-61. doi: 10.1007/BF02126701.
Because physicians use scientific inference for the generalizations of individual observations and the application of general knowledge to particular situations, the Bayesian probability solution to the problem of induction has been proposed and frequently utilized. Several problems with the Bayesian approach are introduced and discussed. These include: subjectivity, the favoring of a weak hypothesis, the problem of the false hypothesis, the old evidence/new theory problem and the observation that physicians are not currently Bayesians. To the complaint that the prior probability is subjective, Bayesians reply that there will be ultimate convergence, but the rebuttal to this is that there will not be uniform convergence. Secondly, since the Bayesian scheme favors a weak hypothesis, theories turn out to be a gratuitous risk. The problem with the false hypothesis comes out in the denominator of the theorem, revealing that a factor which is not a theory at all is being considered in the reasoning. On the old evidence/new theory problem old evidence cannot confirm a new theory so that the posterior probability will equal the prior probability. Finally, empiric studies have shown that current physicians are not Bayesians. But on consideration of Bayesian inference as a system of inference, it can be reasoned that physicians should be Bayesians. However, the problem of physicians' and patients' own subjectivity continue to plague this system of medical decision making.
由于医生运用科学推理来对个体观察结果进行归纳，并将一般知识应用于特定情况，因此有人提出并经常运用贝叶斯概率来解决归纳问题。本文介绍并讨论了贝叶斯方法存在的几个问题。这些问题包括：主观性、对弱假设的偏好、错误假设问题、旧证据/新理论问题以及医生目前并非贝叶斯主义者这一观察结果。对于先验概率具有主观性这一抱怨，贝叶斯主义者回应称最终会趋同，但对此的反驳是不会有一致的趋同。其次，由于贝叶斯方案倾向于弱假设，理论结果成为一种不必要的风险。错误假设问题出现在定理的分母中，这表明在推理过程中考虑了一个根本不是理论的因素。关于旧证据/新理论问题，旧证据无法证实新理论，因此后验概率将等于先验概率。最后，实证研究表明当前的医生并非贝叶斯主义者。但从将贝叶斯推理视为一种推理系统的角度来看，可以推断医生应该是贝叶斯主义者。然而，医生和患者自身的主观性问题继续困扰着这个医疗决策系统。
