I understand the point, that Ussher's chronology (4004 BC, etc.) is not
much different from ICR's. That much is true. But Ussher, who worked in
the mid-17th century, was doing state-of-the-art scholarship at the time.
Incidentally, he was a close friend of Robert Boyle's father Richard, 1st
Earl of Cork, and probably was the person responsible for the younger Boyle
writing an early book on biblical criticism (Some Considerations touching
the Style of the Holy Scriptures), written before any of his scientific
books except (perhaps) parts of the Usefulness of Natural Philosophy.
Ussher relied on various sources, secular as well as sacred, in compiling
his chronology. An important point is that he believed the medieval Jewish
tradition that put 4000 years between the creation of the world and the
coming of Messiah. Given the recent realization (in his day) that Herod
died in 4 BC, you can see where the 4004 comes from. That isn't his only
argument, but he thought it supported his conclusions.
Overall, I'm saying that Ussher used methods that involved lots of
extrabiblical assumptions to interpret the biblical text, assumptions
involving the best scholarship of his day. ICR folk, IMO, also use lots of
extrabiblical assumptions, but usually these do not involve the best
scholarship of our day. At least not as far as I can see.
Edward B. Davis
Professor of the History of Science
Messiah College
Grantham, PA 17027
717-766-2511, ext 6840