“We have intelligent species on our planet that we are not even trying to communicate with.”

Wikimania 2008 Alexandria, press conference, 0'20 (August 2008), asked about Google Knol
Context: We are a passionate community of volunteers who are trying to create a free encyclopedia for every single person on the planet. So we don't often think in terms of competition. We are going to do what we do and we hope Google does wonderful things as well. … If we were approaching this as a business we would think always: Oh, how can we position ourselves on the market... We just don't do any of that stuff.

Artificial intelligence: Should we be as terrified as Elon Musk and Bill Gates? http://zdnet.com/article/artificial-intelligence-should-we-be-as-terrified-as-elon-musk-and-bill-gates in ZDNet (20 October 2015)

54 min 25 sec
Cosmos: A Personal Voyage (1990 Update), Who Speaks for Earth? [Episode 13]

Quoted in "The Olduvai Theory: Sliding Towards a Post-Industrial Stone Age" by Richard C. Duncan http://dieoff.org/page125.htm
Originally from Fred Hoyle, Of Men and Galaxies (Seattle: University of Washington Press, 1964).

How Many People Can Live on Planet Earth? (BBC Horizon, 2009)

Source: Cosmos: A Personal Voyage (1990 Update), Journeys in Space and Time [Episode 8], 54 min 55 sec
Context: Those worlds in space are as countless as all the grains of sand on all the beaches of the earth. Each of those worlds is as real as ours and every one of them is a succession of incidents, events, occurrences which influence its future. Countless worlds, numberless moments, an immensity of space and time. And our small planet at this moment, here we face a critical branch point in history, what we do with our world, right now, will propagate down through the centuries and powerfully affect the destiny of our descendants, it is well within our power to destroy our civilization and perhaps our species as well. If we capitulate to superstition or greed or stupidity we could plunge our world into a time of darkness deeper than the time between the collapse of classical civilization and the Italian Renaissance. But we are also capable of using our compassion and our intelligence, our technology and our wealth to make an abundant and meaningful life for every inhabitant of this planet.

Source: Cosmos (1980), p. 339
Context: Human history can be viewed as a slowly dawning awareness that we are members of a larger group. Initially our loyalties were to ourselves and our immediate family, next, to bands of wandering hunter-gatherers, then to tribes, small settlements, city-states, nations. We have broadened the circle of those we love. We have now organized what are modestly described as super-powers, which include groups of people from divergent ethnic and cultural backgrounds working in some sense together — surely a humanizing and character building experience. If we are to survive, our loyalties must be broadened further, to include the whole human community, the entire planet Earth. Many of those who run the nations will find this idea unpleasant. They will fear the loss of power. We will hear much about treason and disloyalty. Rich nation-states will have to share their wealth with poor ones. But the choice, as H. G. Wells once said in a different context, is clearly the universe or nothing.