Having been born into a highly secular society and raised in an irreligious and agnostic family background, I have been an atheistic materialist and naturalist for most of my life until my late thirties, and was only interested in nature and natural sciences. Due to my popular science interest in modern physics (cosmology, relativity theory, and quantum mechanics) I came to realize fundamental philosophical problems concerning time, causality, and the effectiveness of mathematics. I also realized the hard problem of consciousness, the problem of reason (incl. intentionality /aboutness), the problem of universals, the standard problem of free will, and the problem of objective morality. This led to a spiritual journey spanning about 15 years in search for a coherent world view, which implied the exploration of very different approaches like mathematical monism (Max Tegmark), pantheistic neopaganism, non-dualism (Advaita Vedanta) and neoperennial integral thought (Ken Wilber), Whiteheadian panentheistic process thought, Bergsonian and Nietzschean flux, quantum mysticism with monistic idealism (Amit Goswami), Neoplatonism with objective idealism (John Leslie), and philosophical theism. I then also thoroughly evaluated the pro and con arguments for Christianity, esp. Roman Catholic and Reformed theology, as well as Biblical exegesis and history. My "conversion" from atheistic materialism and naturalism to immaterialism and supernaturalism did not involve any faith in holy scriptures, but was exclusively based on reason and a careful critical evaluation of empirical evidence and philosophical arguments. However, I am convinced that even without sophisticated arguments we can simply know as a properly basic belief that materialism is wrong, that time flows, that we have an immortal soul and free will, that we live in a world with genuine meaning and purpose, that objective moral values exist, and that a spiritual realm and ultimate ground of being (aka God) exists.