What do you regard as the most profound questions /mysteries faced by humanity? My candidates include:
1. Cosmology: How did it all begin, why is there sonething rather than nothing? Physicists are comfortable turning the clock back to the first fraction of a second of the universe, but the models stop working before that.
2. Biology: How did life on Earth first begin? The known replicators are already incredibly complicated. Too complicated to realistically cone together by chance, perhaps suggesting some prior, weaker evolutionary process.
3. Philosophy: What is consciousness, how and why did it evolve?
4. Physics: How should quantum mechanics be interpreted. We have the most successful physical model of all time, on which most of modern technology is based, but everyone is scratching their head as to how to interpret it. Can there really be a multiverse of infinite universes? Why do outcomes seem dependent on observation?