"I asked them to imagine what it would be like if we lived in..." — Ted Chiang quote meaning

I asked them to imagine what it would be like if we lived in a world where, no matter how deeply we dug, we kept finding traces of an earlier era of the world. I asked them to imagine being confronted with proof of a past extending so far back that the numbers lost all meaning: a hundred thousand years, a million years, ten million years. Then I asked, wouldn’t they feel lost, like a castaway adrift on an ocean of time? The only sane response would be despair. I told them that we are not so adrift. We have dropped an anchor and struck bottom; we can be certain that the shoreline is close by, even if we can’t see it. We know that you made this universe with a purpose in mind; we know that a harbor awaits. I told them that our means of navigation is scientific inquiry. And, I said, this is why I am a scientist: because I wish to discover your purpose for us, Lord.