Tricorders and transporters are cool, but the most radical invention on "Star Trek" may have been its vision of a peaceful humanity.

Sure, humans are always getting into fights on the show's original and spin-off series, but generally with other, less "enlightened" alien species. Earth in the "Star Trek" universe is an egalitarian, utopian planet that has long ago shrugged off the habit of war.

People in Star Trek's vision of the 23rd century use their time and talents to explore the universe, create art and probe the mysteries of science.

Sounds nice, huh?

While some have dismissed this aspect of the show as its most fanciful element, psychologists and political scientists say it might not be so unrealistic.

"I do think humans might someday reach more peaceful coexistence if we don't destroy the planet first, though I doubt it will be utopia," said Dennis Fox, emeritus professor of legal studies and psychology at the University of Illinois at Springfield. "If utopia does come, it won't be because human nature changes, or because some governmental authority or alien race forces it upon us, but because we manage to create new social structures more conducive to satisfying human needs and values."

Is violence human nature?

Human nature is compatible with a peaceful existence, Fox and other psychologists say.

An international group of 20 scientists convened in Seville, Spain, in 1986 by the Spanish National Commission for UNESCO came to the same conclusion.

"Just as 'wars begin in the minds of men,' peace also begins in our minds. The same species who invented war is capable of inventing peace," the group wrote in its Seville Statement on Violence.

Not everyone agrees, though. Some scientists say aggression is a fundamental human trait built into us by thousands of years of evolution.

A 2008 study published in the journal Psychopharmacology found that when mice display aggression, their brains are rewarded with dopamine, a pleasure-inducing neurotransmitter. The findings are thought to extend to humans.

"We learned from these experiments that an individual will intentionally seek out an aggressive encounter solely because they experience a rewarding sensation from it," said study leader Craig Kennedy, professor of pediatrics at Vanderbilt University in Tennessee.

Maybe both peace and violence are part of human nature, some say.

"Humans are wired with great potentials for altruism, caring and compassion but also for destructive competition and for killing," said Marc Pilisuk, a psychologist at Saybrook Graduate School and Research Center in San Francisco.

What's our problem?

Besides human nature, the main hurdle to peace is bad government, some scientists say.

"A better world, if it comes into being, depends not so much on technological fixes as on breaking down centers of power so that we can all play a significant role in deciding matters that affect our daily lives," Fox told SPACE.com.

Pilisuk agrees.

"If there is a common enemy around which humanity can unite, it is the institutions that protect privilege for an elite network with extraordinary power and minimal accountability," Pilisuk wrote in an e-mail. "At present, hopes for peace look most promising in the decentralized myriad of creative local actions of people wanting leaders to respond to their true needs."

Taking this idea a step further, Richard Koenigsberg, a former professor of psychology at Queens College in New York City, argues that it's not governments, but the idea of countries at all that creates war.

"Warfare is linked to the human attachment to 'nations.' As long as people believe that countries are the most significant thing in the world and that 'nations have the right to kill,' then warfare will persist," he said.

Perhaps if humans come to see ourselves as residents of a single planet, rather than citizens of individual nations with specific interests, war will be unnecessary.

"War is not part of human nature," Koenigsberg told SPACE.com. "It is intimately linked to our psychic attachment to countries."

Already peace on Earth?

Hope for a nonviolent society might not have to wait until the 23rd century. Peace on Earth already exists in some places.

"Although our own society has a good deal of violence, there are societies which are pretty nonviolent — no wars and very few murders and rapes — and they are not fighting aliens," said psychologist Joseph de Rivera, director of the Peace Studies Program at Clark University in Massachusetts.

The Web site Peacefulsocieties.org lists current and past nonviolent societies. Examples include the Batek people of Malaysia, the Himalayan Buddhist Ladakhi people, The Mbuti rainforest-dwellers of Central Africa, and even the American Amish.

These communities have found ways to resolve conflicts without war, so maybe the rest of us can, too.

"I'm hopeful for two reasons," de Rivera said. "1.) Most people don't like to be dominated by the powerful. 2.) Although we don't have aliens to fight against we do have nasty viruses and global warming that we have to unify to deal with."

There's nothing like a really big problem to bring people together.