This is a much misunderstood topic on what philosophers call a properly basic belief. Dr. William Lane Craig teaches on this topic of Reformed Epistemology.
Playlist: http://www.youtube.com/playlist?p=PLEDED3EA10698ACE2
BELIEF IN GOD AS PROPERLY BASIC (by William Lane Craig)
1. Beliefs which are appropriately grounded may be rationally
accepted as basic beliefs not grounded on argument.
a. Properly basic beliefs characterized
b. Properly basic beliefs not arbitrary
2. Belief that the biblical God exists is appropriately grounded.
a. The Inner Witness of the Holy Spirit
b. Warrant and Christian Belief
c. Defeaters and Christian Belief
3. Therefore, belief that the biblical God exists may be rationally
accepted as a basic belief not grounded on argument.
William Lane Craig and his arguments and evidence for God:
Contingency Argument for God (the Leibnizian Argument):
http://www.youtube.com/view_play_list?p=A7CE655E55212940
Kalam Cosmological Argument for God:
http://www.youtube.com/view_play_list?p=54765A57944CEDDB
Teleological Argument for God:
http://www.youtube.com/view_play_list?p=9A91B68D2FB071C1
Ontological Argument for God:
http://www.youtube.com/view_play_list?p=48F0C019551ADD08
Moral Argument for God:
http://www.youtube.com/view_play_list?p=EB04E423535F5D7C
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