The true aristocrat is never worried about his position; the orator convinced of the truth of his message worries not as to how it will be received; the machinist sure of his plans hesitates not in the construction of his machinery; the architect assured of his accuracy pushes on his builders without hesitancy or question, fear, or alarm; the engineer knowing his engine and his destination has no heart quiver as he handles the lever.

It is the doubter, the unsure, the aimless, the dabbler, the frivolous, the dilettante, the uncertain that worry.

How nobly Browning set this forth in his Epilogue: What had I on earth to do With the slothful, with the mawkish, the unmanly?
Like the aimless, helpless, hopeless, did I drivel -- Being--Who?
One who never turned his back but marched breast forward, Never doubted clouds would break, Never dreamed, though right were worsted, wrong would triumph, Held we fall to rise, are baffled to fight better, Sleep to wake.
No, at noonday in the bustle of man's worktime Greet the unseen with a cheer! Bid him forward, breast and back as either should be, 'Strive and thrive!' cry 'Speed,--fight on, fare ever There as here!' And this is not "mere poetry." Or rather it is because it is "mere poetry" that it is _real life_.

Browning had nearly seventy years of it.

He knew.