If you're lucky enough to live without want, it's a natural impulse to be altruistic to others. But, asks philosopher Peter Singer, what's the most effective way to give? He talks through some surprising thought experiments to help you balance emotion and practicality -- and make the biggest impact with whatever you can share. NOTE: Starting at ...

Why do we prioritize human rights over those of other species? Philosopher Peter Singer dives into what he calls "speciesism," the root of the widely ignored mistreatment of animals around the world, from factory farms to product-testing facilities. He makes the case for ending the commercial exploitation of animals for food and invites everyone...

To protect against a possible resurgence of smallpox, the US government is funding research to improve treatments and vaccines. And since it's unethical to expose people to a highly lethal virus, labs are using monkeys as research subjects. But is it right to harm these animals to protect humanity from a potential threat? Rebecca L. Walker takes...

Musician and activist Peter Gabriel shares his very personal motivation for standing up for human rights with the watchdog group WITNESS -- and tells stories of citizen journalists in action.

Using examples from birdsong, the natural lilt of emphatic language and even a cooking pan lid, singer-songwriter and TED Fellow Meklit Hadero shows how the everyday soundscape, even silence, makes music. "The world is alive with musical expression," she says. "We are already immersed."

Steven Pinker charts the decline of violence from Biblical times to the present, and argues that, though it may seem illogical and even obscene, given Iraq and Darfur, we are living in the most peaceful time in our species' existence.

As a "corporate suit" (his words) and former VP of sustainability at McDonald's, Bob Langert works with companies and their strongest critics to find solutions that are good for both business and society. In this actionable talk, he shares stories from the decades-long transition into corporate sustainability at McDonald's -- including his work ...

In a talk that's equal parts funny and urgent, consultant Vinay Shandal shares stories of the world's top activist investors, showing how individuals and institutions can take a page from their playbook and put pressure on companies to drive positive change. "It's your right to have your money managed in line with your values," Shandal says. "Us...

Fashion designer Isaac Mizrahi spins through a dizzying array of inspirations -- from '50s pinups to a fleeting glimpse of a woman on the street who makes him shout "Stop the cab!" Inside this rambling talk are real clues to living a happy, creative life.

Tod Machover of MIT's Media Lab is devoted to extending musical expression to everyone, from virtuosos to amateurs, and in the most diverse forms, from opera to video games. He and composer Dan Ellsey shed light on what's next.