For some time now, I have seen many posters respond to particular points by citing classical logical fallacies like the argument from authority or bandwagon fallacy (argumentum ad polulum). The problem is, these appeals to logical fallacies are frequently misused. Most frequently, I have seen these fallacies appealled to when scholarly consensus or unanimity is cited in support for an argument.
For example, the question on whether Jesus existed or not has come up again and again on this forum. In every thread, at least once, someone (myself included) notes that virtually all experts agree that Jesus existed. The response is often for someone to shout "argument from authority!!!" or "bandwagon theory!!!"
Both of these are incorrect appeals.
The argument from authority and the bandwagon fallacy are sometimes both referred to as argumentum ad populum, although there are differences. The argument from authority basically says just because an authority says X doesn't make X true. The bandwagon fallacy simply means just because a lot of people believe X doesn't make X true.
Now, it is certainly true that citing scholarly consensus doesn't make one correct, as the consensus can (and has been) wrong.
However, there is an important difference between the above fallacies and citing scholarly consensus.
Consensus is not just a lot of people (or even a lot of experts) saying X is true. It is built on accumulated knowledge and arguments which go through an extensive testing process:
1) Professor Y researches X topic in great detail and determines A, B, & C.
2) Professor Y submits his work to a peer-reviewed journal or academic press.
3) His work is reviewed by other people who are experts in that field.
4) If it is up to snuff, it becomes part of scholarly literature.
However, the process only begins there. Once published, experts from all over review the work and come up with counter arguments or supporting arguments (or both, e.g. supporting A & B but not C). These arguments also go through the above 4 steps in order to become part of scholarly literature.
A consensus not simply from a general agreement among experts but agreement based on these accumulated and intensely reviewed arguments.
In other words, appealing to consensus is NOT appealing to either an authority or many authorities, but an appeal to the accumulated arguments made to form the consensus.
This is a HUGE difference bewteen appealing to consensus and simply saying "X is true because professors A, B, & C say so or "most people believe it to be true (the bandwagon fallacy or the argument from authority).