I was atheistic in my teens & then I turned to Philosophy & the more I delved into it, the more I realized that many of the ideas that I had subscribed to as an atheist just didn't add up at an elemental level ! Even the very building blocks of 'thought' that we've taken up to be sacrosanct were remarkably paradoxical at a very fundamental level & so the more I studied Epistemology the more I realized how true this was & how chronic it had become !
Thats when I realized a series of Philosophical Conundrums & what made me come back to Islam was that the Koran was talking about all of them !