Meaning of the following quotes?

I think what david meant  with the 'I know' statement. He knows the paradise no longer exists, either permanently or temporarily.

It's been a long time since I last posted but I check the site almost every day.

"There is nothing in the desert & no man needs nothing" . I have always thought that this is a direct comment on our own limitations to only see our immediate needs. Thus, to a man, the desert appears barren and devoid of supporting life. However, deserts teem with life.  Life finds alternative ways to survive & multiply. Just because man sees nothing of use or food sources or of any interest, does not mean that life cannot exist there. I believe that David is telling us that just because humans can detect no life signs or radio signals does not mean that there is no life . He is more open minded to the fact that life can exist in many forms. The opposite of this quote would be "There is something in the desert and non-human life needs something".

just found this thread. I think weyland is saying there is nothing for them on lv223 as he has not yet passed to the afterlife to comment that there is nothing, plus david says have a good journey which suggests to me weyland hasn't passed on just yet. in the original spaihts script, david saw things we cant due to his advanced optics. the engineers can also see these blooms/ flows of energy. I think they may have kept this part in the script yet don't make it obvious to the viewer.