Well, I think that when you think about the challenges we face, these are challenges that require us to look forward and not backwards. When it comes to the economy I think we have to recognize that we are now in a global economy. And that the measure of our success is: how well are we training our workers? How well are we investing in the new energy economy?
That is honor's scorn
Which challenges itself as honor's born
And is not like the sire. Honors thrive
When rather from our acts we them derive
Than our foregoers.
Women's Studies can amount simply to compensatory history; too often they fail to challenge the intellectual and political structures that must be challenged if women as a group are ever to come into collective, nonexclusionary freedom.
We'll continue to speak out in a respectful way; never challenging somebody's love for America when you criticize their strategies or their point of view.
Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage - at the very least the courage to question the conventional wisdom.
I may have absolutely no control over what happens to us, but we can control how we respond. If we choose the right attitude, we can rise above whatever challenges we face.
Today I challenge our nation to commit to producing 100 percent of our electricity from renewable energy and truly clean carbon-free sources within 10 years.
One of the things I learned as president is that your life is just not going to unfold the way you want it to. There will be surprises, challenges, and therefore the question is how you deal with the unexpected.
If the imagination is to transcend and transform experience it has to question, to challenge, to conceive of alternatives, perhaps to the very life you are living at the moment.
It is impossible to remain indifferent to Japanese culture. It is a different civilisation where all you have learnt must be forgotten. It is a great intellectual challenge and a gorgeous sensual experience.
Whenever I look at the history of presidents I deeply admire - the one thing that I'm always struck by is persistence. It's a quality that's underrated. Being able to plough through, being able to stay buoyant in the face of challenges.
As a matter of fact, it's in our interests that we help reformers across the Middle East achieve their objectives. This is the fundamental challenge of the 21st century.
We will build our defenses beyond challenge, lest weakness invite challenge. We will confront weapons of mass destruction, so that a new century is spared new horrors.