From Rabbiner Esriel Hildesheimer Briefe by Mordechai Eliav:
This translation comes from Scholarship and Faith: David Hoffman and His Relationship to "Wissenschaft des Judentums" by David Ellenson and Richard Jacobs.
This is from a letter written by R. Esriel Hildesheimer's son regarding the matter of how R. Samson Rafael Hirsch reacted to R. David Zevi Hoffman's book Mar Samuel.
Mar Samuel was a juedische Wissenschaft book; what we would today call an academic study of the third century 'amorah Shmuel. Although it must be stressed that R. Hirsch maintained cordial relations with R. Hoffman, who had taught in R. Hirsch's day school, he was a strident opponent of juedische Wissenschaft. As you can see, he believed it was heresy; it was heresy to write a biography of a Talmudic sage, to systematize his views, to correlate them with his environment and personality.
Thus, R. Hirsch's view. The corrolary, of course, is that R. David Zevi Hoffman felt otherwise.