A skeptic? But if you were there feeling the ground shaking as you read the verse, would you not reflect? It was hard to dismiss. I already believed God existed for an intellectual reason and while that helped open my eyes to the possibility that he was actually present, it wasn't until later that I took to a pursuit.And the Grateful Dead were playing in Oregon, and had just struck up "Fire, Fire on the Mountain" when Mt. St. Helens erupted.
I will give you another experiment then. I have committed adultery with sex outside of marriage. When I did admit to myself why that was so wrong by comparing actions with personal belief, I felt remorse and decided to give my wife the due opportunity for corrective action. I became convinced that I needed to confess it simply because it was a truth that I had buried. That was not easy, but I was relieved that she did forgive me. The next day, within a single day, we received three important phone calls for jobs. Whereas in the prior three or more months we had none. So the experiment is: if you have any sins whatsoever in your history, any lies, buried truths, or even just ill thoughts, then confess them. Do whatever it takes to clear them and to earn forgiveness by seeking change. It is a method to change but I was personally surprised to see the real feedback too. Keep the eyes open and if someone wants the proof, then I believe proof is available to them. The experiment is: be totally honest with others as you wish God to be totally honest with you.
I recently had someone who I was trying to convince of the importance of confession to help clear his record. He has a record and is open about it with me, but that does not buy him as much as being honest to the people that he sinned against and earning their forgiveness. Yet he outrightly was rejecting that as a path for fear of retribution. He said seriously that he believed that the 'christian god' automatically forgives him. So I asked him if someone sinned against him if he would automatically forgive them. He said yes, he forgives everyone. Then I asked him if he would still trust or place faith in the person, and he said no. So I said then you have NOT really forgiven them. I asked if he expected God to trust or place faith in him then? This person was angry that I was telling him what God does or does not do, so I said No, but that you are telling me what you think God is by the way that you treat people. Now, what if someone comes to you and confesses... will you trust them or place faith in them any more? He thought about it and said yes. So I asked will you be more thankful that they confessed their wrongdoing to you, and that they are seeking your forgiveness? He said yes... so, there is the importance of confession. If you want to improve the relationship then there is a tool. Earn God's faith. By rejecting confession I feel that a person is NOT placing faith in God. If you seek in your mind a relationship with God, and the past sins come to mind, then seek resolution to them. Clear them with a real commitment to change. I was not even expecting external feedback at the time, but upon receiving it I had some physical evidence that a portion of every day is not necessarily written by people.
Ok, another experiment: Pray for other people and ask other people to pray for you. Not just in a time of need, but there was an extended family member, Andrew, high school age who was nailed by a vehicle at over 40 mph just last St. Andrews day. He was hit in the head by the side mirror of a vehicle, and then smacked down on the pavement. There was blood coming from his brain and ear. He was in a comma and received open cranial surgery I think to relieve the pressure on his brain and stop some bleeding. His family sent out an appeal for prayer and I was impressed by his dad's commitment to family. I certainly did not think Andrew deserved this so my distant prayer was for a full recovery within one week. In one week he was out of the comma and released from ICU. In exactly another week they released him from the hospital and into physical therapy. In exactly another week they released him from there and he walked home. So in 21 days he walked home and he was then home for Christmas. It did not turn out exactly as I had personally asked, but it was considered an amazing recovery.
While I don't consider that as proof, it was an experiment. There are other more direct avenues, but ask yourself what really constitutes a proof? A hallucination? You would run the risk of doubting yourself, but as you try gravity every day you come to know gravity. Maybe a handful of de-thorned roses every day complete with kisses and an "I love you" in your ear? Does anyone here bother to give God the "I love you" every day? Are you able to receive rebuke? I did not realize that real feedback was available, and I have gained an appreciation for both praise and for rebuke... both are a portion of my proof. Seek your own proof, because I know that I can not prove for anyone what nobody but God could prove for me.