The Philosophers' Cocoon

In our newest “how can we help you?” thread, a reader asks:

I have a question about writing samples…would it be frowned upon to send an introduction to a dissertation or book project in progress as a writing sample? I work in a pretty technical area, so I think my introduction is clearest and most engaging for a general audience. But, of course, it's only the beginning of an argument, and perhaps search committees want to see a full argument in article form? Apologies if this has been asked before.

This seems to me like a mistake. Your research statement should serve as an accessible and engaging introduction to your work. I think you want your writing sample to show your "chops", as it were. It should be a piece that does hard philosophical work, showing your best as a philosopher! 

But these are just my thoughts. What are yours?