In the Coase discussions yesterday, someone brought up the point that all the richness of Pigou - all the public choice etc. - is lost in the textbooks. The guy I was talking to argued that because mainstream textbooks' Pigou is very different from the real Pigou, he is entirely in the right in criticizing this Pigou as fallacious.
This, I think, is a very problematic viewpoint.
Textbooks introduce ideas to students.
Textbooks are not repositories of the history of thought.
You don't find Pigou in the index of a micro textbook, and turn to the page to get an intellectual history of Pigou. You find Pigou in the index to get the page numbers of the selected ideas an economic student should know that are unique enough to Pigou that they are filed under "Pigou" in the index. If you want an intellectual history with all the richness that Pigou has to offer, you go to a history of thought journal.
Grab your nearest economics textbook and turn to the bibliography. Look at how many sources you have cited. If all the intricacies of their perspective were included in the textbook it would have to run to thousands and thousands of pages. It's an absurd standard.
One reaction to this is to criticize mainstream economists that use textbooks to teach students for having a superficial view of Pigou, of Smith, of Coase, or of whoever else. This is not a reaction that pays dividends in my opinion. Even the works of intellectual history that this reaction inspires are disappointing in a lot of ways because they spend too much time targeting textbooks as if those textbooks were ever intended to be intellectual histories.
A second reaction is to know that economics teachers have a limited amount of time in which to communicate important ideas to students. Given these constraints, the best option is to sometimes spend a page teaching the slimmed down discussion of Pigovian taxes, and then indexing Pigou's name, before moving on to Coase, then Lindahl, then maybe discounting future costs, and then moving on to the next chapter.
An intellectual historian interested in Coase, or Pigou, or Lindahl should quite obviously not be reaching for a micro textbook as a source, an inspiration, or a sparring partner.