Is war inevitable? That question has been put to professionals from all backgrounds in the new Brian Lehrer Show series “End of War,” which questions the conventional wisdom behind explanations for mass violence. Celeste sat down with Brian Lehrer, host of our co-producer WNYC’s “The Brian Lehrer Show,” and John Horgan, author of “The End of War,” to discuss what — if anything — can be done to stop future wars.