Cory Cotten-Potter argues it's harder than you think:
When humanity is examined in a scientific context most of the traditional theories are problematic. Man is a rational animal, yes, but the great apes have been shown to be capable of logical reasoning, and there is evidence to suggest that African grey parrots should be added to the list. Man is a tool-using animal, but so are apes, dolphins, elephants, and others. Human dignity as a defining concept offers little help; although it is an integral part of many political, religious, and philosophical texts and may help shape our valuation of humanity, there is no consensus regarding its conceptual origin. Many agree that humans have an innate and inalienable dignity, yet the concept of dignity is usually proscriptive regarding humanity’s actions, not descriptive of humanity’s condition.
(Photo: A chimpanzee in the Budongo Trail at Edinburgh Zoo holds a chimp proof camera on January 26, 2010 in Edinburgh, Scotland. The 11 chimps at the zoo are being featured in a BBC Natural Worl Documentry on January 27. They have been taking part in a voluntary study called "The Chimpcam Project," a collaboration between the Royal Zoological Society, University of Stirling and Burning Gold productions. The chimps have experienced video streaming for the first time, learned how to use touch screen technology and have been given the camera to shoot their own footage. By Jeff J. Mitchell/Getty Images)