Criticisms of probability as being epistenxjlogically inadequate as a basis for reasoning under uncertainty in Al and rule-based expert systems are largely misplaced. Probabilistic schemes appear to be the best way to deal with dependent evidence, and to properly combine diagnostic and predictive inference. Suggestions that expert systems should duplicate human inference strategies, with their documented biases, seem ill-advised. There is evidence that popular schemes perform quite poorly under some circumstances and there is an urgent need for careful study of when they can be relied upon. Some promising probabilistic alternatives are available, but they need to be demonstrated in realistic applications.