The most influential utopian idea of the nineteenth and twentieth centuries was socialism, which has failed everywhere. Under the banner of socialism, Stalin's U.S.S.R. and Mao's China gave us not utopias but ghastly anti-utopias.

The planet Mars - crimson and bright, filling our telescopes with vague intimations of almost-familiar landforms - has long formed a celestial tabula rasa on which we have inscribed our planetological theories, utopian fantasies, and fears of alien invasion or ecological ruin.

We all want a non-fragmented solution, but the utopian version of a single blockchain to rule them all is undesirable and impractical.

I have argued that the Soviet story is one of the interaction of speculative excess or utopian aspirations with refractory reality.

All in all, I don't think robots and greater automation can bring about a utopian world as I imagined it would as a kid 50 years ago.

I've decided to recast myself as Utopian. I like this landscape of the M25 and Heathrow. I like airfreight offices and rent-a-car bureaus. I like dual carriageways. When I see a CCTV camera, I know I'm safe.

In my bright, utopian future world, they will hand out college educations like cups of water at the end of the L.A. Marathon.

When Oscar Niemeyer died on December 5, 2012, ten days before his 105th birthday, he was universally regarded as the very last of the twentieth century's major architectural masters, an astonishing survivor whose most famous accomplishment, Brasilia, was the climactic episode of utopian High Modern urbanism.

Contrary to the utopian rhetoric of social media enthusiasts, the Internet often makes the jump from deliberation to participation even more difficult, thwarting collective action under the heavy pressure of never-ending internal debate.

If utopian fiction became the new trend, I wouldn't read it.

Jews do not have to be Christians. Christianity is an offshoot of Judaism, but too utopian, too hopeful, too unrealistic a turn.

Around 1967 I began backing away from dogmatic Leninism, not so much because I thought it was false, I just decided there was nothing utopian about it.

Maybe it's because I come from a very utopian world of being a comedian, but I'm used to many live comedy performances going on in any city I'm in, and each of us is trying to be the best at what we do. I don't think of it as a competition so much as a thriving comedy economy.

It's a heartening fact about the human race that utopian fiction precedes dystopian fiction in the evolution of literature.

'Divergent' was my utopian world. I mean, that wasn't the plan. I never even set out to write dystopian fiction, that's just what I had when I was finished. At the beginning, I was just writing about a place I found interesting and a character with a compelling story, and as I began to build the world, I realized that it was my utopia.

The false prophets of Communism predict a utopian society.

In their matching candy-stripe shirts, the Beach Boys were America's biggest band of the early '60s, transmitting utopian bulletins of summer without end to a cold and overcast nation.

Nuclear disarmament and non-proliferation are not utopian ideals. They are critical to global peace and security.

Britain rightly sees herself as a global good citizen, but she must reconcile ambition with power, ends with means - shedding utopian idealism in favour of a more rugged internationalism, putting the national interest first, not last.

Although images of perfection in people's personal lives can cause unhappiness, images of perfect societies - utopian images - can cause monstrous evil. In fact, forcefully changing society to conform to societal images was the greatest cause of evil in the twentieth century.