A flickering beacon of science and reason amid cable’s superstitious Dark Ages, “Through the Wormhole With Morgan Freeman” (9 p.m., Science) returns for a new season with its most controversial episode.

”Is There a Superior Race?” goes right to the heart of one of mankind’s most vexing and flammable notions. The mapping of the human genome at the end of the 20th century was thought to have put an end to the idea of race. Since all humans share virtually identical genetic material, differences were dismissed as merely skin deep.

But over the past 10 years, a few scientists have begun to explore some of the genetic differences between racial groups, particularly those mutations that occurred during the past 20,000 years — roughly the span of human history.

Charles Darwin theorized that once human beings formed civilizations, they would no longer mutate or evolve. But scientists have found an astounding number of recent genetic mutations that are clearly responsible for racial differences that transcend skin tone or bone structure.

Europeans have been raising livestock for dairy products for only a few thousand years, yet in that relatively short span they have developed genes that enable them to digest cow’s and goat’s milk. These genes are noticeably lacking in people from Asia, where widespread dairy agriculture never took hold. But it’s a perilous leap from genetic differences in human digestion to theorizing that some races have evolved to become smarter than others.

One pessimist suggests that genetic engineering may enable a handful of people to breed a stronger, disease-resistant race that could dominate the poorer multitudes, leaving them to reproduce the old-fashioned way.

Another theorist suggests that the evolution of the human mind may no longer be taking place in our brains or in our genes, but in our hivelike adaptation of social media. He envisions a future where billions of people linked by technology could solve problems together and advance humanity in ways we can’t even imagine now.

Tonight’s other highlights

• A new baby irks a pampered bulldog on “Dogs in the City” (7 p.m., CBS).

• Toby Keith and Kristen Bell host the 2012 CMT Music Awards (7 p.m.).

• A competitive eater needs medical attention on the season premiere of “Royal Pains” (8 p.m., USA).

• Dani and Matt keep it quiet on the season premiere of “Necessary Roughness” (9 p.m., USA).