Invitation to a Dialogue - Are We Less Violent? - NYTimes.com I have been studying violent events for several decades, so I was deeply interested in Steven Pinker's new book, "The Better Angels of Our Nature," which claims that violence has long been declining and that this may be our most peaceful era in our species" existence. Dr. Pinker argues that, over centuries, human beings have become less prone to kill and engage in torture and other cruel and sadistic behavior. I have not experienced the 20th and 21st centuries that way. My work has taken me to Auschwitz and Hiroshima, and I have come to see these two dreadful events as largely defining our era. Our subsequent development not only in nuclear but also chemical and biological weapons, and our pollution of the planet with our wastes, suggest further directions of mass killing and dying. The deaths over the last two centuries reflect a revolution in the technology of killing. During the 20th century we saw the emergence of extreme forms of numbed technological violence, in which unprecedented, virtually unlimited numbers of people could be killed. Those who did the killing could be completely separated, geographically and psychologically, from their victims. Millions of people were also killed during the 20th century in more old-fashioned, low-tech ways during genocides, induced famines and wars. There is a terrible paradox here. Dr. Pinker and others may be quite right in claiming that for most people alive today, life is less violent than it has been in previous centuries. But never have human beings been in as much danger of destroying ourselves collectively, of endangering the future of our species. We are not helpless about our fate. There could not be a more crucial moment to draw upon our gradual taming of individual violence, along with our growing awareness of the grotesque consequences of numbed technological violence, to achieve lasting forms of what can be called peace. The writer is a psychiatrist and the author of, most recently, "Witness to an Extreme Century: A Memoir." Editors" Note: We invite readers to respond to this letter for our Sunday Dialogue. We plan to publish responses and Dr. Lifton's rejoinder in the Sunday Review. E-mail: letters@nytimes.com