Christian Philosopher Alvin Plantinga's Experiences of God

The following is an excerpt from Alvin Plantinga's Spiritual Autobiography [or archived HERE, or HERE]:

...During my second semester, however, there were two events that resolved these doubts and ambivalences for me. One gloomy evening (in January, perhaps) I was returning from dinner, walking past Widenar Library to my fifth floor room in Thayer Middle (there weren't any elevators, and scholarship boys occupied the cheaper rooms at the top of the building). It was dark, windy, raining, nasty. But suddenly it was as if the heavens opened; I heard, so it seemed, music of overwhelming power and grandeur and sweetness; there was light of unimaginable splendor and beauty; it seemed I could see into heaven itself; and I suddenly saw or perhaps felt with great clarity and persuasion and conviction that the Lord was really there and was all I had thought. The effects of this experience lingered for a long time; I was still caught up in arguments about the existence of God, but they often seemed to me merely academic, of little existential concern, as if one were to argue about whether there has really been a past, for example, or whether there really were other people, as opposed to cleverly constructed robots. Such events have not been common subsequently, and there has been only one other occasion on which I felt the presence of God with as much immediacy and strength. That was when I once foolishly went hiking alone off-trail in really rugged country south of Mt. Shuksan in the North Cascades, getting lost when rain, snow and fog obscured all the peaks and landmarks. That night, while shivering under a stunted tree in a cold mixture of snow and rain, I felt as close to God as I ever have, before or since. I wasn't clear as to his intentions for me, and I wasn't sure I approved of what I thought his intentions might be (the statistics on people lost alone in that area were not at all encouraging), but I felt very close to him; his presence was enormously palpable. On many other occasions I have felt the presence of God, sometimes very powerfully: in the mountains (the overwhelming grandeur of the night sky from a slope at 13,000 feet), at prayer, in church, when reading the Bible, listening to music, seeing the beauty of the sunshine on the leaves of a tree or on a blade of grass, being in the woods on a snowy night, and on other kinds of occasions. In particular I have often been overwhelmed with a sense of gratitude--sometimes for something specific like a glorious morning, but often with no particular focus. What I ought to be most grateful for--the life and death and resurrection of Christ, with the accompanying offer of eternal life--is harder, simply because of its stupendous and incomprehensible magnitude. One can say "Thank you" for a glorious morning, and even for your children's turning out well; what do you say in response to the suffering and death and resurrection of the son of God? to the offer of redemption from sin, and eternal life?- Pages 7-8

 Then later starting at page 17 Plantinga admits,
 

...Mountains have been a blessing: for many years anyway, the Sensus Divinitatis seemed to work most strongly, for me, in the mountains. I mentioned above the time I was lost in the mountains; but on dozens of other occasions I have strongly felt the presence of God in the mountains--although on some occasions what I also felt was guilt and divine disapproval. For if mountains were a blessing for me, they were also a bane. The problem was that (particularly during the first couple of decades of our marriage), I was positively obsessed with mountains.