A (long) profile of Freeman Dyson, uncloseted skeptic, in the Sunday NYT, written by Nicholas Dawidoff:

Science is not a matter of opinion; it is a question of data.

It's rather important not only to be not orthodox, but to be subversive.

... always preaching the virtues of boredom ...

The purpose of thinking about the future is not to predict it but to raise people's hopes.

The truths of science are so profoundly concealed that the only thing we can really be sure of is that much of what we expect to happen won't come to pass.

From last year, Freeman Dyson:

Environmentalism has replaced socialism as the leading secular religion. Environmentalism, as a religion of hope and respect for nature, is here to stay. This is a religion that we can all share, whether or not we believe that global warming is harmful.

Also:

I beseech you, in the words of Oliver Cromwell, to think it possible you may be mistaken.

Colin Powell:

Avoid having your ego so close to your position that when your position falls, your ego goes with it.

Richard Hamming:

If you do not work on an important problem, it's unlikely you'll do important work.

Dyson:

I've always enjoyed what I was doing quite independently of whether it was important or not.

Carolyn Johnson:

We are most human when we feel dull. Lolling around in a state of restlessness is one of life's greatest luxuries.

Michael Lopp:

You should pick a fight, because bright people often yell at each other.

The Civil Heretic