Can we understand consciousness?
What happened before the Big Bang?
How fine-tuned is the Universe?
What is the nature of time?
Is life ubiquitous?
How should we interpret quantum mechanics?
Whence the constants of nature?
Are there other universes?
I returned today, and the essays in the communities pages and thoughts explored in the blogs remind us of how much remains mysterious and unknown, and that in some sense everything fundamental remains mysterious and unknown. I should visit more often to be reminded and to enjoy exploring some of the great mysteries of our strange existence.