However, in a universe where humans exist, there is a human form of life.

"People have been trying for at least 20,000 years to do what we're doing, probably longer - since humans ever existed," he says.

On the contrary, as with her father, these wretched humans do not exist.

Weather, if not climate, has been claiming human victims since humans have existed.

There are those who believe that we humans could not exist without them.

Might Marcus and his ship, left outside, become the only evidence in the whole universe that humans had ever existed?

Whether or not humans could even exist on any of them was a moot question.

To experience the state in which humans exist all the time is new and disturbing.

There is no way, even in principle, to say how many humans might exist in the future.

If humans can exist down here in the wild, then so can we.