Answer:
There is still so much that we do not know.
Step-by-step explanation:
This is true because the author goes on to say despite all of this which he mentions, in the end he speaks of how the far outstrip of our collective comprehensions still doesn't hold that much understanding of what is out there. Which is the premise of his speech saying that without doing things that are difficult we won't learn what we have been yearning to for ages, and that we do them not because they are easy, but because they're difficult