I'm not pessimistic. It is the world that is terrible. How can we be optimistic in the face of a planet where people live so badly, nature is being destroyed and the dominant empire is money?

I'm not an optimist. I'm hopeful.

I am hopeful, though not full of hope, and the only reason I don't believe in happy endings is because I don't believe in endings.

I don’t believe in optimism. I believe in optimal behavior. That’s a different thing.

I don’t have a lot of hope per se. This is a question I get asked a lot, and I’m always like, Why do you think I’m hopeful? I know way too much about the science, that’d be a little bit irrational. But I do think that what I have is a deep understanding of the fact that we still have a range of possible futures. Every scientific report, every graph, there’s a range: We could have two degrees [Celsius] of warming, or we could have four degrees of warming. We could have a little bit of coral reefs left, or we could have none. We could have 20 hurricanes a year, or we could have 10. And that really makes a difference. So basically what gets me out of bed every day is fighting for the best possible future, knowing that climate has changed and will continue to change even if we stop emitting greenhouse gases now, just because we’ve set all of these things in motion.

could still be around. And I am. And for a lifetime, I've been driven to try to respond. I find that the question I'm most frequently asked today is whether I have hope; whether I have hope that our planet can survive. And my answer is: wrong question. It's simply a matter of a job to be done. And I would rather fight than watch, as would you.

I don't consider myself a pessimist. I think of a pessimist as someone who is waiting for it to rain. And I feel soaked to the skin.

I can't be a pessimist because I'm alive. To be a pessimist means that you have agreed that human life is an academic matter.

The the question whether I am a pessimist or an optimist, I answer that my knowledge is pessimistic, but my willing and hope are optimistic.

I do not like to see any thing destroyed; any void produced in society; any ruin on the face of the land.

To the question whether I am a pessimist or an optimist, I answer that my knowledge is pessimistic, but my willing and hoping are optimistic.

I can't be a pessimist because I am alive. To be a pessimist means that you have agreed that human life is an academic matter. So, I am forced to be an optimist. I am forced to believe that we can survive, whatever we must survive.

It is because I reject lies and running away that I am accused of pessimism; but this rejection implies hope — the hope that truth may be of use. And this is a more optimistic attitude than the choice of indifference, ignorance or sham.

I am not optimistic or pessimistic. I feel that optimism and pessimism are very unbalanced. I am a very hard engineer. I am a mechanic. I am a sailor. I am an air pilot. I don't tell people I can get you across the ocean with my ship unless I know what I'm talking about.