Katia, you ask some of the most interesting questions. This question reminds me of two guys I heard talking about sports, they had figured out all the angles and taken into account all the statistics but still couldn't come to an agreement on who would win the game. What they could agree on is, it didn't matter how much they Analyze everything about the game the only way to figure it out is to play the game. So as far as your question goes, "do all our answers lie in the past?" No, that would be too easy, nor will you find all of them in one place, nor will you find one all inclusive answer that tends to cover everything. Life is incredibly complex and you will have to use more than just your memory to find your answers, so I wouldn't take my thinking cap off anytime soon.
I'll apologize for this up front but one could always answer the question,
"Do all of our answers lie in the past?"
"I'll tell you tomorrow."