There is one thing we can do, ...

There is one thing we can do, and the happiest of people are those who do it to the limit of their ability. We can be completely present.
 Mark Van Doren

Quotes from the same author

Any piece of knowledge I acquire today has a value at this moment exactly proportional to my skill to deal with it. Tomorrow, when I know more, I recall that piece of knowledge and use it better.
 Mark Van Doren
Respect for the Truth is an acquired taste.
 Mark Van Doren
To be what no one ever was, to be what everyone has been: Freedom is the mean of those extremes that fence all effort in.
 Mark Van Doren