It’s impossible to “prove” that God exists because, at least as we define Him, He so greatly transcends our limited tools of logic and observation. Nonetheless, if we merely allow ourselves to, we can experience God. I think this is what Rambam had in mind when he placed God in a list of beliefs–rather than presenting an “acid-test” creed, as those looking for any excuse to reject traditional Judaism charge, he was simply telling us that there are some phenomenon which cannot be intellectually grasped and are knowable only via the “Belief Channel”.
The most primal of contests involves exactly two opponents. Perhaps that’s why boxing has remained such a popular sport through the ages. Stripped down to the essentials, without supporting team members, equipment advantages or any other distractions, when two primal opposites enter the ring only one can be victorious. As much as we might want to process opposing opinions as “both/and”, some concepts truly are mutually exclusive.
With this in mind, I propose that each of us, both now and throughout time, have exactly two choices as to how we’re going to live our lives. We can either live as if God exists, giving our lives concrete form, morality and some mandated behavior, or we can live in an “everything goes” mode, convinced there is no meaning to anything we do.
Or, as our tradition teaches, הכל בידי שמים חוץ מיראת שמים, Everything is in the hands of God except the recognition and acknowledgement(1) of God.
(1) יראת שמים (Yirat Shemayim) is often translated as “fear of heaven”. Taken literally, it is based on the root ראה which means to see. I’m translating the word שמים (Shemayim), heaven, as God.