Aren't you glad Acts 4:13 is in the Bible? I am. What does it mean that Peter and John were "unlearned and ignorant"? It doesn't mean they were stupid. It simply means they had no formal education or special training. In other words, the Jerusalem church had no academic hotshots.
God delights in using people who lack professional qualifications and status. I see this everywhere I travel. I see women and men who lack any kind of academic attainment and yet are powerfully used of God, and I mean powerfully. I doubt that Jesus was very impressed with book learning and titles. Not that he would necessarily be against these things either. (Neither am I.) But as Helmut Thielicke says ("Beyond Pushing and Producing," Leadership Journal, Fall 1995, p. 85):
[Jesus] appears not to be bothered at all by the fact that these are not strategically important people, that they have no prominence, that they are not key figures.... He seems to ignore with a sovereign indifference the great so-called 'world-historical perspectives' of his mission when it comes to one insignificant, blind, and smelly beggar, this Mr. Nobody, who is nevertheless so dear to the heart of God and must be saved.
Jesus, says Thielicke, ignored "with sovereign indifference" all the things we elevate as indispensable status symbols -- degrees, titles, attainments, publications, conference papers. And there is a very good reason for it. All the leaders of the early church were men of the Spirit (Acts 6:3, 7:55, 11:24, etc.). It was the Spirit who had made the Ephesian elders overseers (Acts 20:8). The Spirit was the source of their power, their eloquence, their success. The power of the Holy Spirit is such that it can give simple disciples a life and message that can reach every heart. Real Christianity is a very simple thing when done in the Spirit.
A Ph.D. may mean a Phenomenal Dud. We all know people who have been educated beyond their intelligence. And no use in saying that our evangelical subculture doesn't crave titles. If we're not careful, our Bible colleges and seminaries can be squeezed into the mold of this age and become little more than fashion plates. We are not transformed by knowledge alone. We are transformed by the renewing of our minds. The life of the mind itself is a miracle, and every phase of it ought to bear the mark of the supernatural.