Sort of in the same vein as the last post - how we store ideas in our head and how that results in some less than convincing use of ideas.
When we've evaluated an idea as a good idea, I think we tag it as "proven" or even "self-evident" before storing it away. Like the catechismic use of ideas this makes a lot of sense. It would be wasteful of cognitive resources for me to run through the arguments justifying the allocative efficiency of the market every single time the allocative efficiency of the market came to mind. Instead, I tag it as a "good" idea, keep the evidence and arguments on the back burner, and feel comfortable whipping it out and applying it.
Generally speaking that's fine. After all, if challenged we're usually OK at dredging up the evidence and proofs.
But it can lead to blindspots when we go beyond assertion and try to make an argument. Tagging ideas as "good" can lead to lax defense of those ideas because we associate them with strong evidence and proof already - so what's the use of adding more? It's self-evident! We identify the idea with the quality of being well-defended.
I won't go into details because I'm really distracting myself from work at this point, but Bob Murphy has a great example of this with a Paul Krugman post on monetary policy under Lincoln. I thought Krugman's post was a fine post when I first read it (before reading Bob). Made sense to me! But as Bob points out, Krugman offers no real evidence to defend his kinda weird claim that everything was fine in the 1860s and 70s. Krugman may in fact be right. I think he is right. But what a weird period in history to bring up if you want to defend the ideas he presents! There's so much going on - so much noise. And Krugman doesn't even try to present the defense.
On the flip side (since I gave two cases in the last post too), I think you see this a lot with Austrian citation of 1921 or 1946. They've tagged their idea as "good", so they go ahead to latch on to the thinnest of evidence that they think supports their idea, because it's self-evident. (It doesn't need their defense after all - the marginal contribution of effort exerted in the defense of the idea is small, from their perspective). But to outsiders who have not tagged the idea as "good", the major problems with 1921 and 1946 are pretty obvious.