SarahC:

A key thing to consider is the role of the "mainstream." When a claim is out of the mainstream, are you justified in moving it closer to the bunk file?

An important point here is that the intellectual standards of the academic mainstream differ greatly between various fields. Thus, depending on the area we're talking about, the fact that a view is out of the mainstream may imply that it's bunk with near-certainty, but it may also tell us nothing if the mainstream standards in the area are especially bad.

From my own observations of research literature in various fields and the way academia operates, I have concluded that healthy areas where the mainstream employs very high intellectual standards of rigor, honesty, and judicious open-mindedness are normally characterized by two conditions:

(1) There is lots of low-hanging fruit available, in the sense of research goals that are both interesting and doable, so that there are clear paths to quality work, which makes it unnecessary to invent bullshit instead.

(2) There are no incentives to invent bullshit for political or ideological reasons.

As soon as either of these conditions doesn't hold in an academic area, the mainstream will become infested with worthless bullshit work to at least some degree. For example, condition (2) is true for theoretical physics, but in many of its subfields, condition (1) no longer holds. Thus we get things like the Bogdanoff affair and the string theory wars -- regardless of who (if anyone) is right in these controversies, it's obvious that some bullshit work has infiltrated the mainstream. Nevertheless, the scenario where condition (1) doesn't hold, but (2) does is relatively benign, and such areas are typically still basically sound despite the partial infestation.

The real trouble starts when condition (2) doesn't hold. Even if (1) still holds, the field will be in a hopeless confusion where it's hardly possible to separate bullshit from quality work. For example, in the fields that involve human sociobiology and behavioral genetics, particularly those that touch on the IQ controversies, there are tons of interesting study ideas waiting to be done. Yet, because of the ideological pressures and prejudices -- both individual and institutional -- bullshit work multiplies without end. (Again, regardless of whom you support in these controversies, it's logically impossible that at least one side isn't bullshitting.) Thus, on the whole, condition (2) is even more critical than (1).

When neither (1) nor (2) holds in some academic field, it tends to become almost pure bullshit. Macroeconomics is the prime example.