… is from page 161 of Robert Higgs’s October 13, 2013, blog post, “Thinking Is Research, Too! ,” as this post is reprinted in Bob’s 2015 volume, Taking a Stand  (link and emphasis are original to Bob’s blog post):
Bill Parker , an old friend of mine who died in 2000, was director of graduate studies in economics at Yale for thirteen years. He told me once about his struggles with his colleagues, who, he believed, were spending too much time on technique and not enough time on substance in teaching their courses. The recalcitrant colleagues maintained that they were teaching the students how to think, but Bill demurred: the students might be learning how to think, he told his colleagues, but they were not learning anything to think about.