"I do genuinely believe that the political system is not linear. When it reaches a tipping point fashioned by a critical mass of opinion, the slow pace of change we're used to will no longer be the norm. I see a lot of signs every day that we're moving closer and closer to that tipping point."

"Our democracy, our constitutional framework is really a kind of software for harnessing the creativity and political imagination for all of our people. The American democratic system was an early political version of Napster."

"I think the cost of energy will come down when we make this transition to renewable energy."

"I pledge to you today that as president, in my first budget, I will introduce the largest increase in special education ever."

"Being a Christian is more than just an instantaneous conversion - it is a daily process whereby you grow to be more and more like Christ."

"They must often change, who would be constant in happiness or wisdom."

"Organisations are now confronted with two sources of change: the traditional type that is initiated and managed and external changes over which no one has control."

"The echoes of eternity remind us that every challenge is an invitation to grow stronger."