Ussher represented the best of scholarship in his time. He was part of a substantial research tradition, a large community of intellectuals working toward a common goal under an accepted methodology–Ussher’s shared “house” if you will pardon my irresistible title pun. Today we rightly reject a cardinal premise of that methodology–belief in biblical inerrancy–and we recognize that this false assumption allowed such a great error in estimating the age of the earth. […]
The textbook writers do not know that attempts to establish a full chronology for all human history (not only to date the creation as a starting point) represented a major effort in seventeenth-century thought. These studies did not slavishly use the Bible, but tried to coordinate the records of all peoples. Moreover, the assumption of biblical inerrancy doesn’t give you an immediate and dogmatic answer–for many alternative readings and texts of the Bible exist, and you must struggle to a basis for choice among them. As a primary example, different datings for key events are given in the Septuagint (or Greek Bible, first translated by the Jewish community of Egypt in the third to second centuries B.C. and still used by the Eastern churches) and in the standard Hebrew Bible favored by the Western churches.
Stephen Jay Gould, “Fall in the House of Ussher.” Natural History 100 (November 1991): 12-21 (available online here)