According to the famed chronology of Bishop James Ussher, the creation of Adam can be dated to precisely 4004 BC based on Old Testament genealogies such as those provided by Moses in Genesis 5 and 11. Thus, we can be certain that the universe is six thousand years old. Or can we?
First, in comparing Scripture with Scripture, we immediately recognize an omission in the genealogy of Genesis 11. In the genealogy found in Luke 3, Cainan is listed between Shelah and Arphaxad. In the Genesis 11 genealogy, Cainan is missing. While some have ascribed this to a copyist error, all extant biblical manuscripts containing the genealogy—except two ancient witnesses—include the name. As such, through the tenacity of the text, the autograph has emerged replete with Cainan as a legitimate inclusion in the genealogy.
Furthermore, the genealogies of Genesis, in concert with other biblical genealogies, are symmetrical and deliberately arranged. Matthew, for example, skillfully organized the genealogy of Jesus into three groups of fourteen, the numerical equivalent of the Hebrew letters in King David’s name (4+6+4=D+V+D). Thus, Matthew’s genealogy simultaneously highlights the most significant names in the lineage of Jesus and artistically emphasizes our Lord’s identity as Messiah, who forever sits upon the throne of David. Like Matthew, Moses skillfully organized the royal genealogy from which Jesus emerged into two symmetrical groups—ten generations before the Flood (Genesis 5) and ten after the Flood (Genesis 11). Thus, there is ample precedent for seeing the genealogies as symmetrical rather than sequential.
Finally, when Matthew 1:8 lists Jehoram as the father of Uzziah, three generations are bypassed (Ahaziah, Joash, and Amaziah). Thus, far from being the father of Uzziah, Jehoram fathered the line that culminated in Uzziah. This sort of telescoping has significant precedent in biblical history. In the book of Daniel, for instance, Belshazzar is called the son of Nebuchadnezzar (5:2) when in reality he was the son of Nabonidus, the son-in-law of Nebuchadnezzar.
There is a good reason biblical scholars are obsessed with genealogies. While they do not provide a precise chronology between the first and the last Adams, they are rife with theological significance.