The perceptual/mental/conscience-basis for biblical Christianity can be arrived at by a few simple observations and a few self-evident truths.
1) You see life, consciousness, and beauty; you consider the structure of DNA and the design of the cell, and you experience awe and wonder at the unfathomable interconnected complexity of the human brain; you see the incredible diversity of animal, fish, bird, vegetation, and insect life; and you see the seemingly endless stars and galaxies in the night sky. And you ~know~ there is an all-powerful God who designed and created these things out of nothing. You know that He is all-powerful because of the things you can see that exist. God doesn’t need to appear before you for you to have powerful irrefutable evidence for His existence.
2) You know that God is holy and good because you have a strong inborn sense of what is right and good. Where did you get that sense?
3) Further, you recognize, according to Scripture, that the creation has been cursed by God because of man’s sin, with: death, pain, disease, aging, corruption, decay, rust, thorns, and imperfections of all kinds.
4) You know you have done things that were not holy and good: sins and evil. (1 through 4 are observable facts.)
5) You fear, from the holy God, judgment, punishment, death and Hell for your sins, for your evil thoughts and deeds, and for your wrongdoing.
6) You hear the Gospel of Christ and you know that Jesus Christ, God incarnate, died on the cross for your sins, and He rose again on the third day, conquering sin, death, and Hell. You sense Jesus’ unique love, goodness and truth. You know from Scripture that you are, through faith in Christ, forgiven by God, saved, indwelled by the Holy Spirit, and destined for Heaven.
You know these six things by grace, faith, observation, conscience, thinking, and the enlightening of the Holy Spirit.”