One might define adulthood as ...

One might define adulthood as the age at which a person learns that he must die ...and accepts his sentence undismayed.
One might define adulthood as the age at which a person learns that he must die ...and accepts his sentence undismayed.

More phrases

Courage - a perfect sensibility of the measure of danger, and a mental willingness to endure it.
 William Tecumseh Sherman
The same mentality that leads to environmental despoliation, environmental destruction, also leads to damage to people.
 Naomi Oreskes
You can't break poor people mentality. Once you grow up poor, you don't take anything for granted. It can have the negative side also because you can never truly be relaxed.
 Will Smith
The man with the average mentality, but with control, with a definite goal, and a clear conception of how it can be gained, and above all, with the power of application and labor, wins in the end.
 William Howard Taft
I think society had to grow up to the mentality of Peter Norman.
 John Carlos

Quotes from the same author

We learned not to waste ammo even on warriors except in self-protection
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear arms, shall not be infringed. - Second Amendment to the Constitution An armed society is a polite society.
An armed society is a polite society. Manners are good when one may have to back up his acts with his life.
Love is that condition in which the happiness of another person is essential to your own.
Delusions are often functional. A mother's opinions about her children's beauty, intelligence, goodness, et cetera ad nauseam, keep her from drowning them at birth.