Historian Brent Rogers discusses the controversial federal management of the Utah Territory in the 18th century and how it relates current controversies about national sovereignty and jurisdiction.

We have dozens of fruits and grains and vegetables available to us every day, but have you ever thought about where it's come from? No, I'm not talking about if your avocado came from a local or Californian farmer, I mean have you thought about where avocados *really* come from.

For Americans to enjoy avocados today means that at some point in history and American had to hike down to Peru and decide to bring avocados back to the states. We're joined by author Daniel Stone to talk about David Fairchild, an American in the early 1900's who not only brought us avocados from Peru, but hundreds of other plants that we take for granted in the produce aisle today.

Marcus Smith speaks with a political scientist who explains the deliberate polarization of the political parties.

Philosopher George Yancy shares his experience dealing with the backlash that followed the publication of his 2015 New York Times article "Dear White America." He chronicles his experiences and discusses the ongoing problem of racism in his book "Backlash: What Happens When We Talk Honestly About Racism in America."

Kori Schake discusses why the transition from British toAmerican hegemony was so peaceful, and why we probably can't expect thenext transition to follow that example.

Tonight on Thinking Aloud we have an interview about marine debris, otherwise called ocean garbage, otherwise called the watery graveyard for plastic. Whether you know it or not, human debris is accumulating scarily fast in all the world's oceans. Because it degrades on the scale of millenia, most of that junk is leftover plastic. The most famous example of this is The Great Pacific Garbage Patch, a huge gathering of non-oceanic stuff that is the size of the continental U.S. It is a very scary global problem, one that is only now getting on the radar screen of most Americans. Our guest today is the woman who is tasked by the U.S. government with getting rid of and especially preventing more of that dangerous marine debris.

We rarely think about how every man-made objects, from our cars to our phones to our clothing, is colored with a pigment that had to be invented or manipulated by someone at some point. Color is made.

We’re joined by Kassia St Clair, author of "The Secret Lives of Color." St Clair’s surveys 75 shades that range all over the color wheel, unlocking their unique histories and stories.

Sociologist Joel Best discusses his new book, "American Nightmares: Social Problems in an Anxious World" and examines how social problems are constructed and recreated throughout history.

Malcolm Evans, chair of the United Nations Subcommittee on Prevention of Torture and Dean of the Faculty of Social Sciences and Law in the University of Bristol, joins the show to discuss torture prevention and the promotion of religious freedom.nbsp;

You may have heard about or watched the recent launch of the new Elon Musk rocket, a launch that is continuing the forward progress of advancing technology in areas we could hardly have imagined even two hundred years ago.

We're joined by Zach Weinersmith, co-author of "Soonish: Ten Emerging Technologies That'll Improve or Ruin Everything," we'll be talking about some other technologies like Musk's space programs that could be changing our future for the better, the worse, or perhaps just the weird.