Like it or not, life makes philosophers of us all. You may hate philosophy, but you can't escape it. You can - as many people do - outsource how you answer these questions, but that still requires a decision.
5.) How do I know a thing is true? Sometimes the answer is self-evident, but, more often then people acknowledge, it's not. This is exacerbated by the confusion of subjective truth (a personal "truth") with objective truth (the universally true.)
Some people relinquish decision to an authority - be it a teacher, a scripture, or the scientific consensus. Some people only believe what said person's personal experience tells them.
There is a related question of how tightly should one hold onto whatever beliefs one acts as if are true. The scientific approach suggests one should be ready to abandon something one believes is true in light of new information (assuming the new information is sound and can be validated.) Religions tend to prefer that the truths that have been handed down should be grasped firmly no matter what one sees, hears, or learns. One's philosophical stance may take either approach, or one in between.
4.) [Who] am I? As the brackets suggest, this is actually two questions. The full question, "Who am I?" presumes that there is a self (an I.) Some philosophies, e.g. Buddhism, reject this presumption, hence the more fundamental question of "Is there an I?"
3.) What constitutes a virtuous or moral life? Of course, some philosophies would reject the ingrained presumption that one should care, but that's a fringe position. Maybe the more general question of "What constitutes a good life?" is a better one.
2.) What does it mean for something to be real? Some will say, "Come on. I know what's real. I don't need to philosophize about that?" Really? Because the best minds in the world are constantly debating this and have reached no consensus on the subject. It's certainly possible to get through life behaving as though reality is "x," whether or not "x" turns out to be true. But that's very different from knowing what is true.
1.) Is there free will, and - if so - in what sense? It feels like we have complete free will, but there are a couple of grounds on which this has been questioned. For the religious, reconciling an omnipotent god and free will takes some mental gymnastics. (If one can act completely freely, how can a god also?)
But more recently, free will has been challenged by science as well. Benjamin Libet's work showed that "decisions" take place before people become conscious of them, and - therefore - aren't decisions in the sense we usually understand that word (i.e. the product of conscious deliberation.) Of course, while some have argued that the repeated validation of Libet's work shows free will is purely an illusion, there remain many who argue there are still possible ways in which some form of free will exists. (Including, apparently, Libet who believed we at least have "free won't" even if we don't have free will - i.e. we can consciously veto deterministic "decisions.")
Best of luck picking - or building - your own life philosophy.
