On Not Borrowing Trouble

Something about that second sentence: how does he do it?

I saw a delicate flower had grown up two feet high between the horses’ feet and the wheel track. An inch more to the right or left had sealed its fate, or an inch higher. Yet it lived to flourish and never knew the danger it incurred. It did not borrow trouble, nor invite an evil fate by apprehending it.

--Henry David Thoreau, Journal
September, 1850