Science has everything to say about what is possible. Science has nothing to say about what is permissible.

Science has everything to say about what is possible. Science has nothing to say about what is permissible.

When a party is in opposition, it opposes. That's its job. But when it comes to power, it must govern. Easy rhetoric is over, the press of reality becomes irresistible. By necessity, it adopts some of the policies it had once denounced. And a new national consensus is born.

Life and consciousness are the two great mysteries. Actually, their substrates are the inanimate. And how do you get from neurons shooting around in the brain to the thought that pops up in your head and mine? There's something deeply mysterious about that. And if you're not struck by the mystery, I think you haven't thought about it.

If fences don't work, why is there one around the White House.

Pass legislation. When Obama signs, you've shown seriousness and the ability to govern. When he vetoes, you've clarified the differences between party philosophies and prepared the ground for 2016.

The great divide in American foreign policy thinking is between those who believe in paper and those who believe in power.