What convinced me wasn't the pursuit of God through man's understanding or logic alone, being as these things are fallible and mostly based on experience. It wasn't science which led me to this point, considering that science is based on sense perception and proves things only from the fallen nature of this world. I didn't find God through simply thinking, or pondering, or wondering 'this' or 'that' -- all of the methods I mentioned so far are means of trying to comprehend what is incomprehensible. Spiritual understanding, I humbly believe, comes only from God.
As Saint Paul said in his letter to the Corinthians, "What man knows the things of a man, except for the spirit of man which is in him? Even so, no one knows the things of God, except God's Spirit."
Knowing God isn't the result of an academic pursuit, it's a gift from the Spirit.
Even the Apostle Paul didn't preach with persuasive words of human wisdom, but in demonstration of the Spirit and of power, that our faith might not be held in the wisdom of men, but in the power of God. As the saying goes, you can lead a horse to water, but you can't make it drink -- words may lead us to a certain point, but it's ultimately the Holy Spirit which reveals true faith to us, which is quite contrary to the notion of 'blind faith' which some believe is necessary.
As the Apostle goes on to say...
"But we speak God's wisdom in a mystery, the wisdom that has been hidden, which God foreordained before the worlds for our glory, which none of the rulers of this world has known. For had they known it, they wouldn't have crucified the Lord of glory." And surely they wouldn't deny Him today.
But as it is written, "Things which an eye didn't see, and an ear didn't hear, which didn't enter into the heart of man, these God has prepared for those who love him."
"But to us, God revealed them through the Spirit. For the Spirit searches all things, yes, the deep things of God.
But we received, not the spirit of the world, but the Spirit which is from God, that we might know the things that were freely given to us by God. Which things also we speak, not in words which man's wisdom teaches, but which the Holy Spirit teaches, comparing spiritual things with spiritual things. Now the natural man doesn't receive the things of God's Spirit, for they are foolishness to him, and he can't know them, because they are spiritually discerned."
What reason? The Holy Spirit revealed God to me, not because of my efforts alone, but because with a contrite and humble heart I finally sought His face, and as the scriptures say, if you seek with all your heart, you will find.
The mystery of faith is, you believe first, and find God second. That's the divine wisdom in the verse "Whosoever shall humble himself shall be exalted, and whosoever exalts himself shall be abased." A humble, contrite, seeking heart finds God -- not an egotistical, pseudo-intelligent, logical mind; contrary to God. As the Bible says, "Earthly wisdom is foolishness of God", but wisdom as given by God is judged by none.
The major experience which followed was my total conversion, who I was then died, and I became new. Nothing is the same. Many prayers have been answered. Many passions have disappeared. Pride was replaced with humility. Glory to God forever.