How many talks have you heard where the "elder" or in the WT says something like...
"Everywhere science has looked, they have not found life."
That's like going to the shore with a teaspoon, sticking it in the ocean, looking at it and saying - this planet must not have wales in it since I see none in this teaspoon.
P.S. to what Cofty will say probably. The Earth is trying to kill us all the time. We would die of exposure or drowning on about 80% of the earths surface without some form of protection or shelter.
He may elaborate on other points.