Are we to conclude that opinions on matters of [evolutionary biology] are only to be expressed by experts, not mere [lawyers] or other common folk?
Many of us involved with fighting creationism have argued for years that expertise is important in scientific matters. That’s why lawyers like Phil Johnson need to demonstrate their knowledge of evolution before they are taken seriously. Any one can express an opinion, but to be taken seriously on a scientific issue, one must have engaged in serious study of the matter at hand. This, of course, also holds for non-scientific areas of study.
Weinberg is attempting to argue that Dawkins is entitled to voicing his opinion about religious matters, and indeed he is, just as I’m entitled to express my opinion about any matter. Unless Dawkins has demonstrated his knowledge of the subject at hand, one could argue that his opinion on religion is as valid as Johnson’s on evolution or mine on bridge building.
I’m making a general point about the need to demonstrate adequate knowledge of a field. Let’s not get into another discussion about whether Dawkins is right or not.