As people age, they are said to become more "mature." The term implies not only increasing chronological age, but also changes in temperament and outlook that typically, though not invariably, come with age.
The traits associated with maturity are those such as self-control, generosity, and the ability to plan for the future. These sorts of characteristics are conspicuously lacking in young children, and to a more-or-less degree in immature adults. Although the attributes of maturity seem to have little to do with one another aside from being correlated with chronological age they do share a common feature: increasingly broad horizons of perspective.
People who are mature do not focus on themselves alone or on the immediate at the expense of the future. They are able to understand the perspectives of others and exhibit sympathy. They make sacrifices over the long term to secure a better future. They exhibit emotional self control, because they understand other viewpoints and the implications of irrational behavior. They can deal with setbacks and frustrations, because they can draw on experience to anticipate that things will eventually get better.
Maturity seems to be increasingly lacking in our society. In fact, a lack of maturity is the central problem in politics today.
People cannot engage in civil discourse because they are incapable of understanding others' points of view. They pursue policies that benefit themselves regardless of the consequences for others. They even favor policies that benefit themselves in the short run at the expense of harm in the long run. The mature not only care about their own immediate future, but also the well being of future generations. They are willing to compromise because they appreciate the concerns of others and don't feel the need to vilify opponents as evil or ignorant.
The maturity of the founders of this country is palpable when you read what they wrote. Ironically, as our country has matured chronologically, it has regressed emotionally. It is difficult to see a way forward, but another trait shared by the mature is persistence motivated by hope and a determination to move forward one step at a time rather than giving into cynicism or despair.