Presuppositional Apologetics is a method of defending the faith that presupposes the existence of God and the infallibility of Scripture. The Bible alone provides the framework through which all experience is interpreted and all truth is known. According to Romans 1:19-23 we know that all men have a knowledge of God. In spite of this knowledge the unbeliever intentionally distorts the truth and exchanges it for a lie.
This doesn't rule out any use of external evidence such as archeology. Eternal evidence, however, is not the basis of our faith. Recently Fox News printed an article describing the claim that a group of Chinese and Turkish evangelicals had found the remains of Noah's Ark 13,000 feet up on Mount Ararat in Turkey. They said they had a 99.9 percent certainty that their find was indeed the ark. Now Fox has printed a followup article describing the find as a probable hoax -- "at best an elaborate deception." For those of us who rest upon the authority of Scripture this means nothing.
All of creation testifies to the validity of Scripture, but Scripture is not dependent upon external validation. Archeology, when properly interpreted, will always testify that the Biblical record is absolutely reliable, but our faith is not built upon external evidence. The followup article states, "There's never been evidence of a great flood." The reality is evidence abounds, but if one presupposes that the Bible is false no amount of evidence will change their mind. God came in the flesh, performed miracles, and rose from the dead and men continued in unbelief.
As we defend the faith we can go with the confidence that the Bible is true and that all men already have a knowledge of God. And we go with the power of the Holy Spirit who is able to powerfully change the hearts and minds of men. This should give us boldness as we confront the unbelief of lost men.